I need help!!

So about a week after my period ends I get really bad stomache pain and I get so bloated to the point where I look 8 months pregnant and my stomache gets really hard and I can’t even stand up or sit down I have to lay on my right or left side and I don’t know what it is. It hurts so bad I can’t take it anymore. It usually lasts around 5 days.

Does anyone know what this may be?