Light fixture: 3 pairs of wires, two switches
One of the pairs, the one that you originally connected to the light, are the hot and neutral from the breaker box. When you connected them together, you created a short circuit. This is why the breaker won't reset.

Probably one of the others is the switch loop, connected to the light switch on the other end. You need to identify this. If you have a ohmmeter or continuity tester, do the following: WITH THE POWER OFF, connect the meter to the wire pairs until you find the one that opens and closes with the switch. This is the switch loop.

Connect one wire of the switch loop to the hot wire from the breaker panel. Connect the other wire to the hot side of the light. Connect the neutral from the breaker box to the neutral side of the light.

The question I cannot answer is what the other pair are used for. If you fix the light but leave the third pair disconnected (put a wire nut on each wire separately), are there any other outlets or light that don't work? If yes, you probably need to connect these wires also to the hot and neutral from the breaker box. This is used to carry the electricity to the other loads.

If everything is working, just leave these wires disconnected.

Tip: next time you disconnect wires, mark them all with tape to note how they were connected. This may save you a bill for an electrician's visit.