Anxiety Stomachache

hi
today was not an amazing day to say the least. Well, it was ok for a tiny bit of it, but it was pretty bad the rest
so I was supposed to go to this CCCT rehearsal after school today. I was stressing about it all day. I really didn't want to go. I went to one on monday, and it was horrible, boring, and i suffered through all of it. I wish i just didn't have to o CCCT(it's something i started at the beginning of this semester. It's a pathetic drama class full of annoying girls who think  they're amazing actresses)
we're having dress rehearsals this week, and they are four hours long(the show is 45 minutes for heavens sake!) and they are horrible
so i had this horrible stomachache all day today because I was so nervous about going to CCCT. I asked my mom if i could just not go, and i persuaded her to let me go to choir instead(we also have a dress rehearsal)
choir was the tiny bit of my day that was fun. It passed to fast. Then i was in the car with my mom, who immediately ruined my day by asking me why i didn't do my science homework, and how horrible i am(even though i'm doing advanced science for my grade). She also told me that i couldn't go to volunteering tomorrow(I volunteer with a group of kindergarteners at my elementry school-it's amazing that my school lets me do that. Anyways i really love them and it's an amazing part of my day) if i didn't finish my science homework
the thing with my science homework is that i don't understand it. I just honestly don't get it. Its something about the lorentz-fitzgerald light contraction, and it's pretty complicated. I did ok in class with a teacher to help me, but at home it's too hard. I tried looking it up on wikipedia, but it didn't help. Wikipedia is always too complicated for anyone to understand.
so i tried with my dad for help-but that didn't work either, because by this time i was really frustrated. My dad does this really annoying thing where he rereads stuff again and tells you things you already know. Also, if you ask him a question, he answers with a long lecture. He tries to make up things he doesn't know(especially in science. He just acts like they're the truth) so my dad didn't help
and then my mom was just yelling at me that i was behaving really immaturely, not doing my homework and convincing her to let me go to choir rehearsal instead of CCCT

i had a fun time at choir, and at school, but between my mom and my stomachache, i think my mood is bad and annoyed. I'm annoyed at myself.

-eliza