Engine cranks but does not start

Good day. The car may have a fuel related problem. Two days ago, I left from work in the night and I knew the gas needle was on low but I typically put gas in my area to go home right after. I forgot to put gas and headed straight home. The next morning, I knew I urgently had to put gas because the needle was less than 1/4 of the whole tank. So I did, the car turned on perfect before refueling. Arriving to the gas station approximately half a mile away, I put 87 octane fuel (manufacture recommended) at a not-so-great station where I sometimes go for convenience. After refueling, the symptoms began occurring. First start from the gas station, the engine cranked once and turn on immediately. I thought this was odd since my car usually takes two to four turns before it turns on. While driving, there was a noticeable lag when pressing the gas pedal and trying to accelerate under load. Car also sounded like there was knock occurring in the engine area only when under load. Later that day after resting the car for approximately three hours, I turned my car on. This time, the car turned on somewhat fast but then when the car would idle at 1,000-1,500 rpm's, the rpm needle would dip down to about 500 rpm and the car would hesitate/shake a bit, then go back up to idle rpm, then dip back down and hesitate again and so forth. The car luckily worked so I could get to work but before heading to work, it took about two attempts before the car turned on. Leaving from work at night, the first initial start for the car was rough. I pressed on the gas pedal so the engine wouldn’t shut off. I made I home luckily. The next morning was when it all went downhill. Tried to turn the car on, the engine would only turn over but not turn on the car. A couple attempts later and pressing the gas pedal, the car turned on for a mere five seconds, a cloud of gray smoke exited the exhaust, and then the car shut off. That attempt was the last attempt I tried and I determined it was due to a faulty fuel pump or not enough fuel pressure. Sorry for the long story I’m just trying to be very detailed. I really appreciate your help and any advice you may have and thank you for helping.