I just replaced my starter thinking it was the problem and it worked, my car started the first time. Then, i came back to it a few hours later and tried starting it, but it wouldnt start. All it did was make a clicking sound. No turn over or anything. I popped the clutch and it started: i tested the starter at Autozone and it tested fine.

Check the connections to the starter and to the battery. You are looking for corrosion or dirt. Anything that would make a poor connection. It sounds like your battery might be going bad. Worst case scenario is the ignition switch, but I doubt its that..good luck

The starting circuit is remarkably simple. Its basically ignition switch to starter cut relay to clutch switch to starter magnetic switch to ground. I completely second 1fastrx7Turbo's summary : check the battery terminals first (must be clean and solidly fastened), then check the battery itself to make sure its well charged and holds its charge, then if that's all good, go through the electrical chain. May be the starter cut relay is fux0red up or the clutch switch is becoming intermittent. Your starter magnetic switch MIGHT be iffy but I doubt its that if you just replaced it. Those things are remarkably durable. Check the FSM and the wiring diagram as necessary to visualize the circuit.