Frustrated!!!!!

So last month was really strange. I started my period on the 13th like usual but what wasn’t usual was that instead of my flow being heavy and lasting 2-4 days it was light and lasted 7 days. I was done on the 20th, on the 25th I started again and the same thing, light and lasted for 7 days, but one of the days Was slightly heavier, then this month on the 5th I spotted for a day very lightly and then nothing. I took a PT yesterday and it was negative. Today I did not start like usual.