Almost (every) company out here, wants you to (opt out) of paper, thus they bill you by email and you go online and make the payments (or) they automatically w/draw from your account. So, if you had done this, then does not matter if going to school, on vacation or even if you move, since you will always know when something is due vs letting your insurance lapse.
If the officer did give you a ticket, then most likely will be found at fault. Now, if you had not your insurance lapse and (if) there is/was a dispute of fault, then (your) insurance company could have fought for you.
So, you have at least 3 problems. The 1st is, if the trucks insurance does in fact find that you are liable, and if so, then you will have to pay for the truck's damages, and (if) the driver and/or any passengers are in the truck and claim injuries, then you would owe for that also.
Your 2nd problem is that you let your insurance lapse, thus Nationwide should have notified them of no insurance, and (usually) when that happens they put on (forced) insurance which only pays for the damages to your vehicle, but pays (zero) for the trucks damages. But, if they did not add the forced insurance (yet), then your lender could force you to pay off the loan in full, since now that it is damaged, then the loan on the vehicle is worth very little (especially) if the car is totaled or not.
The 3rd problem you will have is that since you had no insurance and if in fact you are held liable, then in most states they can suspend your drivers license and registration till you pay off the other trucks insurance in full.
You might want to talk to a lawyer for legal advice.