I have been absent in school for the last few days because of stress -my head hurts, I have a hard time breathing, my chest hurts and I can't sleep well. And it doesn't help that even when I was absent, I still had a lot of schoolworks to do, so I couldn't take a rest.

I've been absent for more than a week now, and I've just consulted with my pulmo doctor and I'm not sick or not even an asthma attack like I first thought, so I guess it's really just stress.

However, given that I'm not really sick, I'm really frustrated that I haven't been going to school for a while that I want to get sick with a "big" disease, to have a legit reason for being absent :(

Anyone else like this?

You should probably just look into schooling alternatives and discuss it with your family.

maybe you should actually go to school, even if you feel "sick". Those are only used if the sickness is possibly contagious, or if you are unable to get out of bed. If you are able to move around still, and do normal activities, then you are not sick.
But if you want a disease, go to california, and lick the ground, kiss a hobo, get stds