Pregnancy test came back negitive but symptoms are still there was it to early?

I took a pregnancy test on march 14th it came back negitive but I'm still having all these symptoms that come with pregnancy. I have fatigue like crazy, nausea but no vomiting, heartburn, I've just started to get lighthead the past 2 days when I stand or when I'm walking, I have these pains in my stomach like sharp pains not cramps I looked it up and it was said its from constipation and gas I've never been constipated before so I never knew it felt like this. My are tender to the touch but the rest of my aren't sore. And the past week I've had an unusual taste for tarter sauce which I normally hate. The test (which btw was a cheap 99cent pregnancy test) came back negitive tho. But then again my preiod isn't due till aprox, the 29th. Should I wait and take another test. Or am I just buggin?