What should I do ?!

When I get my period on the very first day I get severe cramps, headaches, constipation and vomiting🤮 It’s only ever the first day and it’s happened 3 times now. It doesn’t happen every time but has became more regular since November. I had sex in December and has happened twice since then and once before which doesn’t make me think I’m pregnant. What do you think I should do 😕and does it happen to any of u ??