Everything you describe can be caused by hormones. I get all those symptoms during my period.
Well if you have had sex, then you may be pregnant. You can take a home pregnancy test 2 weeks after having sex or take it after a missed period or an off/different than normal "period" for the test to be accurate. It's also a good idea to take the test with first morning urine, as that is the most concentrated. Though in general, symptoms are completely unreliable in trying to figure out if you are pregnant or not. These symptoms may also be from stress, illness, a hormonal change, or something else. Take the home pregnancy test and then go from there. Good luck.