I think you do yourself a wee bit of a disservice. You just didn't get castled which left your king exposed and he had to do the walk of shame around the board until checkmate.
If it's helpful, I think I would have played 0-0 instead of a3 in your position. Or tried to press the centre with e5? a3 just felt a bit tepid to me.
You'll get me one of these days. @Aim Here almost got me!