Help did I have implantation?

So I’m so confused right now. I have been waiting for my period since the 21st I test 2 days after my missed period and negative. On the 28th of Feb my boyfriend and I were intimate unprotected and I was bleeding a little. I assumed oh I started my period. Monday I had spotting and today there is nothing. I have regular periods and usually are normal. Should I test and if it’s negative what could it be? I have no other symptoms besides missed period and I was cramping last week.