Had protected sex jun. 23/29. period due july 14. it is now 3 days late. white discharge (normal i think) slight cramping. preg or just stressed?

Preg. unlikely, but: A urine pregnancy test, done correctly, gives a reliable result 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and thus lead to a repeat test. If a woman gets her normal regular period, then she is not pregnant.

Protected from what?: Do you mean STD protection or contraceptive protection? If it is the former, run a pregnancy test. If it is the latter your period may simply be delayed and if it is still a "no show" after one week, then run a pregnancy test because contraception sometimes fails.