Does progestogen-only / Mini pill cause irregular periods?

I took this on and off during covid 19 then had a break then went back Oct 2023. The first time around it was amazing no unwanted side effects, very effective. I took a break because I was not sexually active. When I went back on it in Oct 2023 my experience was the complete opposite. The 1st month was fine then I had constant spotting for the nextnear 2 months I could not cope with it and eventually stopped taking it. Then my period did not show up for a month but eventually came back.

This is an easy and quick contraception method which I have found really beneficial to me personally. My periods have now essentially stopped, with very irregular periods now being the norm with my last period being over a year ago. Because of that, when I get a period it is only a few days at a time, whereas before they would sometimes last over 2 weeks. Menstrual pain such as cramps, lower back pain etc are also a lot more controlled. I still get these every month or two but they don't last for long and the pain has decreased massively although I do get breast tenderness more than I used to pre-pill. The downsides though do include acne which has had periods of improving/getting worse and weight gain. Overall though, I like the ease of this (mine is the 12 hour mini pill) compared to other options out there.

The only side effect I had on this pill was the irregular bleeding. It worked for the first 2 months and then I just bled for the next 4 months (until I stopped). I suffer from VERY painful periods and even when I wasn’t bleeding or it was really light I can recall having 3 huge pain episodes that would last a few days. The pill didn’t affect my mood, but the side effects did because I had to spend nearly all summer inside because of the anxiety and depression. Aswell because of the bleeding I lost interest in sex (again, not caused by the pill directly). Overall I’m disappointed this method didn’t work. If I didn’t have bleeding and unexpected cramps this would’ve been perfect.