Progesterone only pill

Sorry some TMI

I was wondering if anyone else put there is on a progesterone only birth control pill? I started taking one about 2 1/2 months ago and last month I had some breast tenderness but had a period as normal. Now this month my boobs hurt bad especially the niple. I remember there was a day or two I forgot to take my pill and took it late. I'm afraid I'm pregnant. But I've also read it could be a side effects the pill. Has anyone else had anything like this?