I was supposed to get my period a week and a day ago but I still haven't. I experience massive cramps when I work out but no other signs of pregnancy, and I took a test yesterday but it was negative but it's only been 11 days since I last had sex. Should I be concerned?

If it is just 11 days since you had sex, while if pregnant you can miss this period, it may be too soon to get a true test. Best to wait till next month and see if you have that period ( unless you have one before) so wait till next month to see if you have that period