Hi Eloise and welcome to AA!
Sorry to hear about your air pump. Sometimes when they burn out or suddenly stop during a power outage, they can cause water to back siphon through the tubing.
Two and a half months isn't a very long lifespan for a new airpump. Do you still have the receipt and warranty? What brand was it? I've been happy with my 2 Tetra Deep Water air pumps, which have both been running quietly for about a year. When you buy another pump, get a one-way check valve (costs about $1.5). Check valves can be installed anywhere between the pump and the aquarium, and they will prevent floods caused by back siphoning.
If you are running a power filter, the fish should be OK so long as you can see ripples and disturbances on the water surface. You could lower the water level a bit or adjust the filter return so that it creates more splashing. That would keep the water just as well aerated as an airstone until you can replace the pump.