lower back pain that is sometimes severe, pregnant?

I am on Loestrin 24 birth control and in February for about a week I was sick and throwing up at night after I took my birth control. I had unprotected sex during that time. That month I had brown discharge that came out of me a week before my period was due and when my period came it was short and light, my period in march was short and light as well. This month my period was normal and came when it should. But I have lower back pain that is sometimes severe, I am peeing more often than I normally do, my nipples are darker, I feel nauseous sometimes, I have headaches, constantly tired, light cramps in my lower tummy and my lower tummy has a hard bump in it that extends along my lower tummy. If anyone can help me that would be greatly appreciated.