1991 Oldsmobile Cutlass Knocking

Here is the story of what has happened so far. I bought this car a few months ago with 88k. It had no problems that I could hear or see, and I have done every little thing I can to keep it running strong. A week ago I decided to act a fool. I stopped on an old highway road, put it into neutral, reved it high, threw it into drive, and took off. Immediatly I heard a low quiet thund and it had no problem getting up to 6k, but stayed there a bit too long before it shifted. I continued driving normally until I got home 10 miles later, and when I put it into park, I heard out of no where a ticking noise. It was constant, but not too loud. Probably twice per second. The next day I started it and it sounded fine idelling. I put it into reverse and started to back out, and I heard it start. It was louder than the previous night, and as I picked up speed, it grew louder and more rapidly. On that trip I noticed that I was showing low oil pressure, so I stopped at Autozone and picked up a 5Qt bottle and put 3.5quarts in with a bottle of motor honey. After 5 minutes of driving it started to quiet down, but it was still there. I didn't drive it the next few days. Then I brought it to a friends house so that we could take a look at it. When I started it up after those few days, the noise was louder, more like a knock, and there while idelling. I ran up do dollar general and grabbed a bottle of Lucus treatment, dumped it in, let it run a few minutes, and drove it to my friends house. I took off the valve cover in the front, the 6 rocker arms where nice and tight, so I took them off one at a time and looked at the push rods. None of them were scratched or bent, and all 6 of the arms were squirting out oil. Today I drove it back to my friends house, and now it is getting worse. It is taking longer to shift, and I have a loss of power. It wont shift until 3.5k no matter how lightly I am pressing on the gas. My friend and I aren't mechanics, but if we knew what the problem was, we could figure out how to fix it. I am really low on money right now, and am hoping that perhaps there are a few cheap things that I can try before I give up on it. Any input would be really appreciated.