Late period

I haven't got my period for 8 months now and I took a pregnancy test when I was 4th month and it said I wasn't , so it was several times my bed n I had sex without a condom but he always pulls out. But I have been having headache my back hurts I feel dizzy and really tired. And I haven't took a pregnancy test but I know I am not cause I don't have the symptoms of me throwing up in the morning or the food discuss me in the mornings. I  have been eating a lot and weight hella weight. I used to weight 150 n now 189 in 1 month