What Causes Delayed Periods With Very Light Bleeding?

Hello, I have a question about my Menstrual cycle. I have always had very heavy periods. They also have always been constant. They always come the same time each month and they are fairly heavy. My last normal period was on Thanksgiving and I went without December, January, but now in February I finally got it. But this one is much different. It is very light. I used to have to used super heavy tampons and change them every 2-3 hours but now I m not bleeding enough to even use a tampon. I have had ovarian cysts that have ruptured before but it was only once 2 years ago. I haven t had sex in a year so I know it has nothing to do with pregnancy. Thank you for your time.