Anyone else have this problem?

I'm 10 weeks pp and for some reason everytime I try and put a tampon in within the hour it's poking out, before I got pregnant they would stay in just fine, but ever since giving birth they legit wont stay in! I hate wearing pads but that's what I've been having to do. I know I'm putting it in right I've been using them for years and years. Idk maybe it isn't the right shape anymore to hold it so it comes out?? I have no idea what would make it so it comes out everytime