Could I be pregnant??

I'm 18 and ive been on Implanon for almost the full three years, September will make it the end of the three years. I haven't had my period the whole time nor any other problems until now. Ive been very stressed and It was two weeks ago when I last had unprotected sex with my boyfriend and this week I have been having some problems that concern me to think i'm pregnant. I very tired and often need to sit, pee every 10 min, certain tastes and smells that usually don't bother me but now do such as garlic make me want to throw up , im nauseous all the time and late night will wake up to throw up. Also gettin horrible cramps. tonight I took two digital test and got negative soo idk whats wrong..