Something's wrong with my body, and no one will help me.

Ok, I don't know if I am more worried or anxious about what has been going on with my body. Basically, I've missed two periods, not uncommon for me, but as my Fiance and I are sexually active, we've used condoms, but have recently gone without. About a month ago, I started to feel kinda crappy, and it's gotten progressively worse. My back hurts, I feel like I've been repeatedly punched in the ovaries, I feel nauseous half the time, I'm bloated, all signs of pregnancy. But here's the problem- every single pregnancy test I have taken has been negative (we're talking probably 15iah at this point). I even went to planned parenthood to get one done, and that came out negative like the rest (and of course they were of no help, all I got was the "keep using birth contol and talk to your GP about your inconsistent cycles. No shit Sherlock). I have had inconsistent periods my entire life. I've gone six months or more without a period, and all I get from doctors is "there's nothing to worry about, you just have a different cycle pattern" or "loose weight and everything should be fine" (I'm overweight, but not obese), and every other excuse you can think of. My periods have gotten heavier and more painful the older I get, some days I can barely functioning. On top of feeling like my lady organs have been run over by a truck, I've had some issues with rectal bleeding, moatly.light bleeding, which was chalked up to constipation or diarea, but there was a LOT of blood the other night when I went to the bathroom once. The urgent care doc said that as long as, ahem, stuff, looked normal, it was probably an anal fisher or hemeroids. I'm almost convinced that the two aren't connected somehow.

I am just concerned as to.what the hell is wrong with me. I'm absolutely miserable in my current state, and it juat keeps getting worse. Of course pregnancy.wpuld be the obvious answer, but my gut tells me it's something else. Endo and polycystic ovarian have been mentioned to me by friends and family, and I have the genetics that tends to favor ovarian cancer

Am I just nuts? Something isn't right, I know it, but no one will help. Any suggestions ?