Stupid question probably but I really don’t know

So every time me and my boyfriend have sex, when he goes in too deep it hurts so much we have to stop and I start crying cause of the pain .. i don’t think this is normal and every time I go to the gyno I forget to ask what’s wrong with me .. it’s all consensual and I love him , but I just really don’t know what’s wrong the next day I’ll wake up with cramps and lower back pain.. does anyone know what’s going on with me ?!?