34 weeks!

I am 34 weeks pregnant now and for the past couple of days I have been having really painful cramps in my lower pelvic area. I dont know what this is. They are not constant most of the time, they usually come and go. Sometimes these cramps are accompanied by back pain. If anyone has any insight on what you possibly think it could be or if you've experienced the same have some advice! I have an appointment next week and will definitely bring it up but until then TIA!