Having cramps and no period?! HELP

Olive
So my period is two days late and this isn't some pregnancy scare thing I've never had sex. I'm just looking for advice. I keep having cramps and they are starting to get bad but my period hasn't came yet and I'm having a friend over on Wednesday to swim and I don't want to be in pain the whole time she's here. On the first few days of my period my lower back hurts nonstop and I get crazy cramps and heavy flow.  I think it might be me stressing out over nothing but I'm worried.  Any advice would be really nice and things I could do to help. Thanks you!
******EDIT
Thank you guys for your comments!!! Period came but it's really light but who cares