What could be wrong with me?

On and off for the last 2 years my period will randomly skip for 6 months then it will come back like normal.

I went to the doctor they did ultrasounds, blood work, etc and everything came back normal. I ended up getting pregnant with my daughter in the middle of not having a period for like 4 months. After I had her it came steady for about 8 months then it stopped again.

What do I do??? I’m so lost. Currently on month 5 of no period once again. It’s so odd to me?