Most insurance companies give you a discount if you drive on "average" of 20 miles or less per day. The reasoning is that the fewer miles you drive, plus the fewer hours on the road, makes you less susceptible to being in an accident.
Since your policy is SPECIFIC of 2,501 to 5,000, most likely when you took out the policy, they asked you what is your mileage and you gave to them. Whenever you have an accident and on ALL estimates, they will list the mileage of your car, plus make/model etc.
Call up your insurance company today and report that you will need to change the mileage restrictions on your policy. Yes, you will be paying more for your insurance and they "might" backtrack to when you changed jobs to the increased mileage. But,,,,,,,if in an accident, and if you never report this, they could DENY your claim for fraud.
Do it now, before an accident, pay the higher premium, so you wont have to worry.