Women's Health

Ok, so here is the deal. I will be 27yrs old next month. I have 3 living children and had a miscarriage back in 2007. My period is not always normal, but I do have one every month. Most of the time it is on time (give or take a few days). I had a tubal ligation back in 2008 immediately following my 3rd and final c-section. I have problems with this brownish/pinkish discharge all the time. Mostly it follows my period, however sometimes it can come before or even just whenever it feels like coming. I was told that it is coming from where I bleed so much during my monthly so my doc has put me on b/c pills to try to regulate my period. I've been on b/c pills for about 5mos now. I feel like my period was just finally starting to become normal and now I am 3wks late. Along with being 3wks late, I am having every pregnancy symptom under the sun. Almost vomited yesterday evening. I have been peeing quite frequently (even if I don't have much to drink). Metallic taste in my mouth, gas, bloating, cramping, back pain, etc. The list could go on and on. Oh yeah, and I never spot. Well, I was at the beach with my boyfriend a few weeks ago and I spotted. When I went to the bathroom and wiped, I thought I was starting my period, so I found a tampon and put it in, but little did I know, the bleeding had already stopped. I am really doubtful that I could be pregnant due to the tubal ligation with b/c pills on top of that. So what the heck is wrong with me here???