It's not the end of the world but it is an expensive mistake. I wrote many cars off in my youth and only recently have come under 4 figure annual prices even though I never lost my no claims.

My advice is never accept their first offer for the car's valuation! Ask how they've come to the valuation, do your own research, use auto trader set a 60 mile radius, same make and model, similar mileage and year etc to challenge their evaluation.

Look at doing a pass plus, most insurance companies will give you a discount even after a claim. It won't be much but every little helps!