URGENT

so my period only last like 4 days at the most and today is the last day right .. so last night i got this huge pain in my abdominal area , at first i thought it was a huge cramp but nah it had to been something else. I got out of bed and kneeled on the floor thinking it would make me feel a little better but it didn’t. I went to the bathroom and used it and got a hot water bottle and placed on my uterus area and it helped a little bit i had to use the bathroom again and it felt even worst. so today it starts again to where i could cry and my legs felt weak just like last night .. should i go to the ER or wait it out being that it could be something pertaining to my period ?

p.s sorry it’s so long ☹️