I don't know what is going on..

Okay, so I need a little advice here. I am on birth control but about three weeks ago I was having morning sickness as you call it for about a week straight but it would go away around lunch. I took a preg. Test and it came back negative. I have been spotting for the past month or so only after having sex. Now I don't know if that's normal...
•Every single time we do have sex it hurts.. Last week it was way more blood than usual but I just can't figure out what is causing it. Please let me know what y'all think..