Nie rozumiem! (Or, adventures with Polish grammar)

Just finished the second day of the two-week Polish language class I'm taking here (Monday wasn't officially a class day, since we just had our language tests and placements and then a pronunciation workshop). It's a lot more difficult than I expected - the classes are conducted entirely in Polish. Most likely this is one of the best and fastest ways of learning, and I'm learning a lot in such a short time, but I feel like I'm having a really hard time keeping up. I'm not sure if this is just my own frustration at thinking I understood something and then realizing I had no idea, or if I really am getting behind in the lessons. On top of that I've been randomly getting up at 6 a.m. and therefore going about my day tired and annoyed because I haven't slept enough. Yay, jet lag.
Either way, I suppose this kind of frustration is something anyone spending any amount of time in another culture or learning another language runs into...I guess the important part is recognizing it.
Prior to coming here, I studied Polish for a year (3 quarters) through Rosetta Stone and LiveMocha (basically a free version of Rosetta Stone, and with a social networking component...rather awesome site), and also met up with a few Polish speakers around the San Diego area. UCSD doesn't have Polish classes per se, but they do have a program through the linguistics department called the Language Lab (which is amazingly awesome for those of us who want to learn languages that aren't as commonly taught at the university). Students can sign up for a 2- to 4-credit class, which gives us access to self-teaching materials (there are several different curricula you can choose from; one is Rosetta Stone, and they also have textbooks and, I think, video courses of some sort). We learn on our own using the material, and then take a midterm and a final each quarter. There is an instructor of record who assigns grades, but the exams are scored by the software.
Having gone through the Rosetta Stone program was pretty informative with regard to basic vocabulary and common expressions, and so I'm able to communicate at a very basic level and, at least some of the time, be understood (I hope). However, the Rosetta Stone software works by showing pictures and the corresponding words in the target language - there are no translations at all. (Incidentally, LiveMocha's is structured the same way, but you can click on a button and get a translation if you want.) Which is good because it forces you to think in the language you're learning, but it works better for some things than others. Grammar, for instance, is really difficult to get across without explicit explanations. Some of the time I could infer what was going on, but more often than not I had to post on forums, ask someone, or just guess.
The class I'm taking here is really helping to fill in the information I'm missing with regard to grammar, rules of the language, etc. (Now if I could only keep up with all of it!) Polish is a much more complicated language than I realized! First, there are the verbs and their conjugations to learn. (I'm not going to go into much detail since I'm pretty sure there's a lot I don't understand yet, but Polish Blog, among other sites, has some useful explanations.) The verbs (as in many other languages) are conjugated according to first/second/third person, the number of people involved, (sometimes) gender, etc...there are a few different categories of verbs that have different conjugations, in addition to the irregular ones.
In addition to basic verbs, there are different prefixes and derivations. Sometimes these form completely new, but related, words, and sometimes they distinguish between perfective verbs (having to do with actions that have been or will be completed) and imperfective verbs (having to do with actions that are taking place, but are not necessarily completed). (For instance, the verb "czytać" means "to read," but if you add the prefix "prze-," which means roughly something like "in front of" or "before," to it, you get "przeczytać," which can either be a perfective form of the verb or can mean something like "to look over"...I think. If any Polish speakers are reading this, please correct me!)
The nouns and adjectives also change, though, because the Polish language uses declension. I had seen the word changes while I was studying with Rosetta Stone, but wasn't sure what they meant. There are a lot of other languages that use it too (Latin, Greek, and German, as well as other Slavic languages, are a few, but there are a lot more), but I had never learned it explicitly before (the only other two languages that I've studied, other than English, are French and Japanese, neither of which uses anything like it). So I spent this morning trying to teach myself what the different cases referred to in preparation for encountering them in Polish. (Surprisingly, the WikiBooks entry on the Polish language has actually been pretty helpful.)
These are just a few of the grammatical aspects of Polish. Interesting stuff, but incredibly complicated, especially when I'm feeling pressured to learn all I can while I'm here and surrounded by Polish speakers. I'm also, intentionally or otherwise, learning a lot about the limitations of language self-teaching, as I'm now encountering all the (as it turns out, fairly important) things I didn't learn from Rosetta Stone. Hopefully by the time I head back to San Diego, I'll have enough of a foundational knowledge of both vocabulary and grammar to keep learning and practicing without being completely bewildered.