What's happening??

I really need help. I think that i am pregnant but everything says that i am not. I am 2 weeks late for my period, i have abdominal aching on the left side,i get really tired easily, i feel sick most times and i have funny light headed headaches.
I have done about 6 home pregnancy tests and they all have been neg. i got my doctor to do a hcg blood test last week but that was neg as well. i don't know what to do because i do want to be pregnant but everything that is going through my mind in very negative. Please help i really need advice!!!!

Have your doctor check your thyroid levels, hormone levels, and do an U/S on that left side to rule out ovarian cysts.

Well since the last post, i have found out that i am actually pregnant. About 8 weeks roughly. My doc has no reason as to why the blood test came up neg apart from low hcg