What Causes Low Cervix With Pain In Abdomen?

hi, i have had the implant in my arm for 3 years now but it ran out on the 10th of this month. i had sex 3 days before it ran out, on the day it ran out and 2 days ago. I have had the feeling that i am due to come on for a week now tho so did not think i could get pregnant. but so far nothing has happend! my boobs are sore and i have been feeling sick for 3 days now but put it down to a tummy bug. i dont no if this will help but my crvixs is very low and i keep getting pains in my tummy. AM I PREGNANT?