Cannot poop, filled with stool. Help me.

I can't go #2. My stomach is so distended that I look pregnant, it always hurts, I'm always full, and tiny amounts of food make me feel stuffed. My doctor told me to exercise, drink Miralax and lots of water, and eat lots of fiber. I've been doing this for a while and it isn't working. I did 2 enemas, neither of which worked, and also laxatives and milk of magnesia which did. I went a LOT, yet there is still tons of stuff in me! My doctor referred me to a Gastroenterology place, but it's completely booked until July. Every single one other than that one will not take anyone under 18; I am only 16. I dont know what to do! I'm also having some other weird symptoms, for example bleeding two weeks after my period, and it's dark brown and not red. I also have some blood that came from my rear, which is red. No, I am not mistaken. It's very strange. I don't know what to do. This problem is taking over my life and there are no doctors to help me.