My car might be getting written off and it isn’t my fault. My car is on finance have gap insurance

Can someone please explain what happens in the following situation?

Someone has crashed into my car today whilst I was not in it. They have admitted full liability, but it looks like a write off. We are just waiting for confirmation. I don’t understand fully what happens now. This is what I think will happen, if someone could confirm or correct me please, I would be so grateful.

These figures are not exact, just estimates.

I bought my used car just over a year ago for £6000 on finance, which with any added extras and interest came to about £8,000. I paid a £200 deposit and I took out gap insurance.

I am guessing that what will happen is:

They will value my car at say: £4000. That amount is paid to my car finance and my gap insurance covers the missing amount, for example the remaining £4000.

So, I am left with no debt but no car either.

If this is true, I can’t see how it is fair. I been paying off my car for over a year now and have paid back around £2,400 so far. If my thinking is right, I am left with out any money to buy a replacement car and will have lost the £2,400 I have paid so far.

I really hope I am wrong! I would be very grateful for any help!