Help..

Okay, so just gave birth to my daughter on April 12th. I started my first period since birth on June 5th, it ended on the 9th. Now I’ve noticed since yesterday, I’m bleeding again. Not enough to have to wear a pad but maybe a liner. I just notice it when I wipe though. I also started back on birth control and a different one then I was on before so I don’t know if that’s what’s causing this or what. Does anyone know what it could be?