1996 Pontiac Grand Am Major engine(?) Problems

In July, I bought a used pontiac grand am and it now currently has 92,000 miles on it. Recently, the engine had started making a strange ticking noise and would sound louder while driving. I ignored it, but a few weeks after that I noticed it was eating up almost a full tank of gas in a very short amount of time. Next, the car began to stall at times. If I stopped and parked and then went into drive, it would sometimes stall. After that began to happen, my battery went dead and I had to get a new one but problems persisted. Finally, at times, the car would not pick up speed if I hit the gas. Going up hills, I worried if I would make it up there. While all this happened, the engine kept getting louder. What could be causing this fiasco?