Help me!

I am 17. I have been experiencing pelvic pain for over a year now. Its debilitating..I also have dark brown gunky discharge CONSTANTLY. I have the Paragard IUD. I also have extreme fatigue and a neurological disorder called POTS( my blood pressure falls and pulse rises upom standing) I recently got an ultrasound and a 2.7 cyst was found on my right ovary. Since, i have passed brown feathery tissue..i took a bath got out and saw it all floating in the tub. I also have a hard tender HUGE  softball sized bulge in my lower left abdomen mear my left ovary. My doctor isnt helping me he says its IBS but it cant be the cause for my discharge and foday i feel like my organs are being sucked out of my tailbone area. ): I just want someone to help me. I am miserable 24/7. Please if anyone has any input on my words or these pics of my belly and US, PLEASE comment.