I have had to start an 18-month program from scratch because I made it so poorly that it was no longer functional. It feels bad, but ultimately it was the right thing to do.
The new version of the game was only similar to the old one in spirit, but it actually got finished, and I guess that's the main thing at the end of the day.
I'd suggest you do try and start again, it's just a learning experience after all.
it's hard to not get emotionally attached to your work, but if this is the correct move then you have to push past that feeling.