What is this strange l discharge?

In the past two or three days I've been having this brown discharge. At first it was just spotting and a fair brown color. Now it's getting a bit heavier and darker. When it began getting heavier, it had a bit of light blood but the blood got more blood like but still a little. I noticed after I urinated today, though, that when I wiped and threw the paper in the toilet I had a big red stain in it that kind of looked lumpish but im not sure. I have to wear kotex at the moment. This discharge is accompained by a sore itch down there that also gets a bit of a hot feeling sometimes. There is no smell, visible rash, green or yellow color, white lumps coming out, or pain besides the soreness. Im an 18 yr old female with hypothyroid. I suffer from depression and joint pains. I am ually active with a friend. We use a condom toward the end of before he ejacualtes. He says he has no other partners but you cant ever be too sure but he has no signs of an infection. He is my only partner. What could be wrong with me? Rashes happen to me because of allergies but in diff. parts of the body. I also get cyst around my lower back and thighs from time to time. I tend to skip out on my medicine (synthroid) a lot. Could i ber pregnant or miscaried? Do I have an infection or hormone disorder? Whats wrong with me?