IUD BIRTH CONTROL

I was on an IUD for 4 years. I didn’t have a cycle the whole time. When I got it removed I bled a little bit but still no cycle. 3 more years pass with no birth control and no cycle. The doctors weren’t worried but I was. Now I am in a new stress free loving non abusive monogamous relationship i have had 5 periods in a row faithfully on time like a normal cycle. Has anybody else experienced this or heard of it ? Does anybody know what’s going on now ? I’m thinking several things. 1) I’m finally happy and not stressed so my body can regulate the way it’s supposed to, or 2) I’m getting closer to 30 (I’ll be 29 next month) and my body is turning into a nesting ground before she runs out of eggs.