My period is 72 days late and I my test is always negative

I am 72 days late on my period and I know for a FACT I'm pregnant. The home test keep saying negative. I mean my appetite has changed my husband can even tell I've been eating a lot more lately and I have been getting sharp pains in my breasts and it comes and goes. I have a bubbly feeling in my stomach sometimes and I think it's gas but it isn't.