You are describing symptoms of pregnancy. If you have had unprotected sex or if your partner has not worn a condom and you have no other contraception, it could be very possible that you are pregnant. If, however you have not had unprotected sex then it is probably your homones changing or you're soon to be expected to get your period. if symptoms persist and you have not got your period, I suggest you do a pregnancy test or see a doctor and they will do a urine test and possibly a blood test If the urine test is positive or if the results came back inconclusive.
How long have you been feeling this way ? Are you sexually active?