TTC Advice Needed

I ovulate this week. I had sex over the weekend several times. But I also had a very light and super short "period" this month. I honestly don't know what to think. My boobs hurt so much today. It could've been implantation bleeding earlier in the month (it was too light to be an actual period forreal). I need advice. I'm in my early 20's. I feel so horrible every time I take a test and it comes back negative. But I haven't taken one since my short visit. Idk. Help me out.