Lower Abdomin mid pain

Im 19 years old, I have been in a serious relationship for 4 years. I am having unprotected intecourse and would welcome a child if it happens. But I have had pains in my lower abdomen , but mid section of it. It started to the right , then left, now mid. It is a pain that stays doesn't leave when it starts. I have taken Home tests they came out neg. though. I have had these pains for 2 weeks going on. I just lost my insurance becuase of my age. I also have had very late periods for the last 2 months. My last period was 8 days late and not to be gross but I have followed my cervix for awhile, The thing i have noticed is it is high very soft, and in a way open. Could anyone tell me any possiblities ? i have no pain during urination, no itching, I feel sick alot, I have a very tender stomach also???????? Any sugg, or answers will be greatly appreciated....[/b]