I feel pregnant but negative results?

I have been feeling very different the past week or so, my tummy is bloated and i get light cramping sometimes. I have also been feeling very exhausted and at times even light headed. My last period came a week early (aug.5th -12th) and was very different then usual. I would spot off and on and for the constant week and a half. It was very weird, then when my normal period date came (aug.13th - 24th) it stoped completely. Since then Ive been feeling very weird and very aware of my tummy area. Ive never felt this way before. I went to the clinic on the 21st and took a pregnancy test wich came out negative. I still had doubts though, I took another pregnancy test today (aug. 24th) and it still came out negative. Ive been researching though and searched when my ovulation time would have been if my period started on the 5th of aug. like it did and the results showed I would have been ovulating frim the 15th to the 19th and it said it takes around 10 days for the egg too latch and that pregnancy test may not be acurate until after this point. Im not sure if Im getting to crazy about this but I have thought I was pregant before and once i got negative results that was that and i forgot about it, somethings just feels so different this time. Plz help!!