having unprotected sex leaves you with a HIGH risk of an unwanted pregnancy occuring...i'd suggest a) going on birth control or b)using condoms EVERY time if you don't wish to be pregnant...bc you're playing with fire...sooner or later it will happen if you continue to have unprotected sex...not only that, but if it is with multiple partners you are also at risk for contracting an std
since you have been having unprotected sex there is a chance that you are pregnant...like i said earlier, i would strongly advise you to go purchase a pregnancy test and go from there...but these "symptoms" you're having wouldn't be due to pregnancy, its too early..if you are indeed pregnant then those symtoms and the pregnancy are probably just a coincidence...as I said its too early for pregnancy symptoms to be occuring