Spotting/irregular periods

Me and my husband had sex on the 14th. It wasn’t rough just a different position than usual and it wasn’t painful. To be honest it was so wet I couldn’t feel much and right as I asked him if he wanted to change positions he said he had already came inside me. I was shocked as I didn’t feel anything at all. Anyways I go to the bathroom clean myself and we go to sleep. Next morning I wipe and there is “old” like blood and some discharge on the toilet paper. I think “yessss finally got my period”… wrong. For that whole day and the next there’s no more blood. Then on the 16th and 17th, it happened again. Only once on those days when I wiped. I’m irregular and sometimes skip up to 4 months and I took a pregnancy test a month ago and it was negative…but is this normal? I’ve never “spotted” like this so I’m slightly freaking out something could be wrong with me. I’m almost 2 months late. What would you do and has this ever happened to you?