i used to get the worst cramps before my period too. it's like your body is preparing you for what's about to happen, but in the worst way possible.
honestly, it's because of hormones that cause your uterus to contract, which can be really painful.
try doing some light stretching or a warm bath to help ease the cramps, it might help you feel a bit better and it's something to look forward to when you're feeling miserable.