When do periods return?

I tried depo for the first time on Sept 5, 2024. I was off bc for a year prior and had very normal and regular periods. I didn’t like the side effects so I didn’t get the second shot when I was due Nov 21, 2024. I haven’t had a period since October and it was unusually light. I also stopped seeing the guy I was with in October. I’ve taken 2 pregnancy tests, one in December and today, both negative. It’s almost 3 months no period. I want my body to feel healthy again.