It Hurts!!

So I am in a lesbian relationship but I’m bisexual I’ve had sex with men I noticed back in 2022 with my ex (a male) that I would experience bad cramping and stomach pain after sex it only happened twice and then I was single now I am with my girlfriend and her and I mostly use hands and mouth or toys but not much penetration we recently bought some dildos and it happened again after sex like this terrible stomach pain at first I thought maybe the size but like I’ve had that before so I don’t know what the cause is. Has anyone experience this or have any ideas what it is?