Went off birth control in June 2019 and went 190 days with no period.

Doctor put me on Provera and I had a 7 day long period. I then started Metformin and had a normal 28 day cycle. The bleeding was really really light but still there.

I have doubled the amount of Metformin and am 2 days late on my period. Not pregnant.

Is this normal to have different cycle lengths every single month, even while on Metformin? I feel like I'm working backward and I'm just in the WORST of moods.