Help?!

So after having my 2nd child November 18, 2018 I didn't start my regular periods til February. I had my period for February March April June I skipped May and July and in August it was extremely light almost like spotting for 4 days and I had gotten negative results on pregnancy tests (2 at home 1 at the doctor's office). Now this month it said I should have started my period on the 12th but didn't and on the 18th when I had used the bathroom there was a pinkish red color on the toilet paper with a couple tiny clots. I assumed my period was going to start so I got a tampon and even put a pad on just in case, but later when I went to change the tampon there was no blood at all... I still left the pad on just to see and still there was never anymore bleeding except a tiny spot but that was it, next day there was nothing at all and there hasn't been since then so far. Is this normal after having your 2nd child or should I be worried? I had always had regular periods before both before and after having my 1st child so I am unsure of what is going on. I did take 2 at home pregnancy tests and both were negative. Please let me know of I should be worried about it or not, I am going to see the doctor aswell but just wanted to come on here to see if anyone else has had something like this happen before. Let me know please.