Help... I'm scared

So I am on birth control and when I was on my placebo last I had dark brown blood(it was more like mucous) that lasted less then 2 days. This was 2 weeks ago. I am taking my birth control normally and on time. I have been waking up nauseous and heightened smell last week. Today I went to work feeling awful I started to bleed a little bit when I wiped. I have a fever and crazy bad cramps. I don't know what to do. I'm really sleepy.  Also this overwhelming sensation to vomit but don't. Any advice?