By now I have developed all of the playing ability I would need, but still cannot be handed some sheet music and know exactly what to do and when 30 seconds later.
Those things contradict each other-- if you don't know what to do, you don't have the playing ability. You can't be said to have learned something apart from your ability to use it correctly when you're actually playing-- at least as far as jazz is concerned.
But I would say that my playing, aside from not being able to always nail the intros and the endings, is exceptional. I can play almost anything I've heard in a Jazz tune. But the combo is like you say, nobody communicates, no greetings, no goodbyes. The instructor always seams like he's in a bad mood, and seams to me, to be very single minded and ridged in how he wants everyone to play. I have the feeling he may be deliberately trying to trip me up, embarrass me and discourage me so that I'll quit.
Maybe he sees that you are overestimating your own abilities, and is trying help you understand some areas where you need to improve. The fact that you don't know some extremely basic things about notation suggests to me that he's right. Don't take it personally, take it as a challenge, and rise to it.
It's very easy to wash out and never learn to play, and have lots of people on the internet to commiserate with about how jazz people suck and are mean and no fun. It's easy, but it sucks. Failure sucks.
Anyways, can anyone explain some of the not so obvious aspects to this music (attached)? Like what does the circle with the cross over it mean? What do the right angles labelled '1.', and labelled '2.' mean? After going through the form the first time, then what? How do I know when the ending will be? What does "D.C. AL (circle with cross)" mean? Where it says "(To Solos)" it seams that the bar before is not actually played right before going into the solos. What does the horizontal dash below '(To Solos)' mean?
OK, here we go, Jazz Charts 101:
1) What's the title? Have you heard this one before? You should have-- it's PENT-UP HOUSE, one of the most famous tunes in the world. Remember how it goes on the record and play that.
2) Upper left. Is there a style indication? Yes. It says "medium-up swing." Play that until it's time to stop.
3) What's the meter? 4/4. If no style is indicated, and you don't know the tune, you can guess that it's going to be a swing feel, or maybe a straight-8th feel, or maybe a ballad. You can go with your best guess when somebody counts it off-- and quickly correct if you're wrong--or you can ask what the feel should be.
4) What's the form? How many measures is it, and what is its structure? In this case, it's 16 bars long; four 4-measure phrases, structured AABA. Count up the number of measures, looking for obvious repeated sections, double bars, and/or rehearsal letters. Forms are often 12, 16, 32, or 36 bars long, with AABA, AB, or AAB structure.
5) What's the road map? This chart has some repeat signs, first and second endings, and a coda sign. TC explained what those are, so you should be able to figure out when to go where. On this chart, it's completely linear and self-explanatory:
a) Start the tune.
b) Play through the first ending, where there is a repeat sign.
c) Jump back to the last repeat sign, in measure 2.
d) Play through the song again, skipping the first ending and playing the second ending.
e) On the second ending it says "to solos", and below that is a 16-bar repeated passage that says "solos" at the top-- play that section many times while different instruments solo.
f) At the bottom of that solo section, there is an instruction: "After solos, D.C. al [coda]. Take repeat." That means "jump to the beginning of the chart and play up to the coda sign, at which point jump to the coda." The "take repeat" instruction means just that-- play the melody twice, with both endings. When you get to the crosshair coda sign, jump to the coda sign at the bottom of the page and play that. That's the end of the tune.
6) What do the chord changes tell you? Not much, at this point in your development. There is one symbol that will be important: N.C.. That means "no chord", and it usually suggests there is a break-- the rhythm section rests on that measure.
7) What does the written melody tell you? This is a rhythmically active melody, and if you choose, you can help outline it on the drums. Listen to some recordings of it to get an idea of what is expected.
8) What do your ears tell you? Probably 90% of the tunes I know, I've never played with a chart. I don't know the title of half of them because I often didn't hear it called before it was counted off. I huge part of jazz drumming is playing with no chart and no information. This tune is very distinctive and pretty straightforward, and you can easily play it by just listening to what the band is doing.
You now have 100% more information about jazz charts than I had when I started playing jazz. I think you should sit down with a recording of the tune, and the chart, and keep listening until everything here makes sense to you. Good luck.