Drinking when possibly pregnant

This sounds horrible. But I've been thinking I'm pregnant. My period isn't late yet , and the test I took was negative. So tonight I went out and had a few drinks. Also last night. Both night I drank a lot more than normal and both times I was hardly affected. I'm normally a big light weight. So I'm not use to being able to have 5-6 drinks and not feel a thing. All I've gotten was a tummy ache.... Anyone have any advice or times when they were pregnant and alcohol affected them differently? Again, I guess I shouldn't be drinking but my test was negative so I didn't think it would be a big deal. Thanks guys!