Why am I expieriencing all the pregnacy symptoms?

I have not had my period in about four months, with the exception of one about two months ago. My period has always been on again off again but this is the longest it has been missing. I have taken two home pregnacy test, and even went to planned parenthood and they all came out negative. Yet i am expierecing some of the symptoms like fatiuge, slight crpaming, stomach firmn but only on the top (squishy on the botom), bloated, and constipation. awhile ago I use to get alot of headaches too. I havent had in almost a month and I took all those test weeks after. I have started eating healthy and working out alot. Im just wondering do I need to go to the docs? Am I preggers? And if Im not, why am I going through all this?