Experience with POP?

The pill I’m on right now (6-7 months) has been working fine but it recently just started causing my periods to be irregular and longer. Sometimes I get my period and sometimes I don’t. But when I miss my period, the next month it comes and it’s longer and heavier. I’m wanting to see if anyone has any experience with taking POP (progestin only pill). Please give me any information you can! It can be the way it made you feel, what it did to your periods, etc.

Also, how do you switch pills? Do you just immediately start taking the next type of pill when you’re done with your current pack? And is it okay to switch back after a few months if it causes symptoms or anything?