New comer to birth control!

So I recently had a baby about 4 months ago, and then started birth control almost three months ago. I had a period in July after I started taking BC June 28th, but didn’t have one in August because I didn’t know there was a week where I stop taking it to have my period. This month I took my three weeks worth and stopped for the 4th week like I’m suppose to do. I’m having some cramping pains, and only bleed for like an hour then again later on. I’m not sure if it’s my period because of how inconsistent it is and light. I would really love opinions.