Low water pressure

I have a submersible pump on my well. I have the state industries premier diaphram tank. I only have a main breaker on my meter box, not an additional breaker box. Three weeks ago my main breaker started shutting off. We could reset it and all would be okay, we had water again. This mainly happened after it rains. Today after we reset it, our water pressure was really low. Could we need to add air pressure to the tank? We've had this tank for around 6 years now. I thought that it was the type that you never had to add to, but I may be wrong. Could we have a short somewhere, but how would that affect the water pressure? Any help would be appreciated. The pump was last pulled around 4 years ago and all the wiring was replaced.
Thanks,
Merribeth

Is the meter serving only the pump? It would be unusual to have only a main breaker serving a residence.

Tripping during wet could be associated with tripping a GFCI breaker. Is it a GFCI breaker?

What is the Amp rating of the breaker?

Can you cause the pump to start and operate while you are present at the tank? Then watch the gauge and note the time from start to stop with the water usage off. If you get very fast cycling, that means the tank is waterlogged, due to inadequate air or incorrect air pressure setting or a failed bladder in the tank. Frequent starts cause a lot of heating in the breaker which can cause the breaker to trip.

Does the pump have a control box or is it controlled only by the pressure switch?

You said the wire was changed four years ago. Did you mean the wire down the well? If so, the wire in the ground if it has a nick or is breaking down would short out when it rained. It happens all the time here.

bob...