Why won't my 1998 Chevy Malibu start after stuttering to a stop and powering off?

[kailana3625]

I purchased my car used just this past October, it is used with 114,000 miles on it, shortly after I bought it the check engine light turned on. I went to autozone to get the diagnostics done and they told me that it was most likely just the fuel cap. I bought a replacement, but the light never turned back off, I didn't think much of since it seemed to be running fine...until recently. In the last month or so my car has stopped while driving three times, after the last time, which was today it won't turn back on. Before the car turns off, it feels as though it is running out of gas, the first two times this happened my fuel had been low, so since then I have kept the gas up, this last time though, I had a half tank of gas and it won't start, it acts like it wants to, and I did get it to start a couple times, but it ran so rough, and the second I got it into drive, it just turns right off, also right before it stopped the oil light came on, and when I try to start it it turns on, but I checked the oil and all seems to be fine. I thought maybe it was my fuel pump, but when it is switched to the on position, you can hear it humming, of course I am no expert, so this could still very well be the problem. I was just hoping for a couple other suggestions. Anything would help, thanks so much.