What is going on?!?

My boyfriend and I started trying for a baby. My period has been very strange this month. I got it on the 8th which was a day early than I was suppose to get it. Which has never happened before if anything my period is late by a day or two. My period is always really heavy. This month it’s light. Alittle more than spotting I would say I had my period all day on the 8th then half way through the day on the 9th it just went away it completely stopped. Until the 10th around 4pm I started spotting alittle then it went away again until today the 11th I starting spotting again. It’s just enough spotting on the 10th and 11th that when I wipe its faintly there. I know sometimes you can have implantation bleeding but for it to go on for 4 days so far doesn’t seem right. My period has never acted like this before. The 8th was probably the only day I would fill a whole tampon (Ultra) because thats the only ones I had laying around. I took 2 pregnancies tests one on the 9th when it stopped and again on the 10th. They both said negative. I’m not sure if it’s just to early to tell that I am or if I’m just not pregnant. I also should mention my normal periods are never short they are always atleast 5 days. Has this happened to anyone else to have light bleeding for couple days then find out they are pregnant?