i have missed my period two months in a row, pregnant?

I have missed my period two months in a row and up untill now i have had one ever 28 to 30 days that lasts about five or six days and in march i had a period for two days that was really really light. I have taken seven home pregnancy tests one was positive the other six were all negative. I have also been nauseous, had heartburn, peeing frequently, my apetite has changed like three times in the last three or four weeks. I have been really tired lately and when i do go to bed i cant get comfortable. Could I be pregnant? Im really confused because i had two negatives after the positive.