"An ambulance driver invests 40,000$ in a retirement account for 1025 days. The interest rate is 5%, compounded every 2 months. What will his final balance be?"

I got to $2,813,025.57
After plugging it into the formula: A=P(1+r/m)^mt

It seems kind of large so I was wondering if that was the right formula to plug that into/if I did something wrong.

1025 days is only about 2.8 years, so yes, it is quite large.

40000(1+.05/6)^(6*2.8) = 45,984.27

Clearly you misused the formula ...
Next time, show what you did.