Weird period??!! Help?!

My period is normal. Always on time and 7-8 days long. Very, veeerrryy heavy. It’s always been like that since I was a teenager. The last 2 months my period has been late and then there’s one spec of blood and it’s done. Last month it was 2 weeks late and there was only one wipe of blood in the morning for 4 days. No blood later in the day, only in the morning. This month it was 5 days late. I thought I got it yesterday but it was very light when I wiped, so I put a tampon in over night and there was no blood on the tampon when I woke up!! And so far I haven’t had a smear of blood yet today!

What could be going on? I’m not pregnant, have taken 7 pregnancy tests in the last 2 months.