What could these symptoms mean?

I am a 16 year old overweight male. For a while I have been having minor stomach pains, headaches and trouble sleeping but recently it has gotten much worse. Now I feel nauseous all the time, have major stomach pains, headaches, am extremely itchy, painful bowel movements, shortness of breath and sometimes I get extremely frustrated at the slightest thing even though I am generally a mellow and calm person. Furthermore there was a dark liquid excreting from my belly button a few days ago that could have been blood and throughout my life it has always hurt when I tried to clean my belly button in the shower but recently the pain has been nearly excruciating and there is a sticky substance that excretes from my belly button which has a horrendous and a lot worse than usual smell. I am scheduled for a doctor's appointment in a few days but I would also like a few more opinions.