Period every two weeks

Hey I'm a mom of a 5 year old and fraternal twins 2yrs. My 1st was normal but the twins were two months premature. I have normal period usually but for the past four months I've had a period twice a month. I also am very tired all the time, nauseated, hot flashes like you wouldn't believe, cramps down to my kneecaps, I've been sexually active hoping to conceive and just ovualted well I hope and think I did and I'm hoping I'm pregnant but ive been feeling weird a couple days I'm also 25