In my experience, it was quite a while before I reckoned I was back to normal.
During pregnancy I had that dozy, slightly detached feeling about things...not necessarily unpleasant but sometimes annoying for others. Mostly I had it at the start, I think, then it went away nearer to the birth.
After the birth was a total muddle for weeks ...but then so it is for everyone, especially for the first baby .
Overall I'd say it was about 8 or 9 months after the birth until I was feeling almost back to my pre-pregnant self.
Congratulations and try not to worry about it.
By the way, I have always struggled to remember where I have parked my car....it's the hardest part of shopping as far as I'm concerned.