Hi there! I was in Korea last year for about 2 weeks as well and I bought around $1k CAD equivalent for food + spending. Personally, I would say it's more than enough
For street food, each item may costs around $4-5,000 won on average. (myeong-dong area). As for cuisine in mid-tier restaurant, pricing for main courses are usually below $20,000 won unless you opt for fresh seafood/kbbq which can varies depending on the restaurant
I also did some cooking during my recovery and I would suggest you to visit local supermarkets for groceries instead of big shopping malls. Groceries in malls tend to be pricer and I made the mistake by purchasing there in my first few days. Try to use Navermap to find local supermarket near your place
Hope my experience helps! Cheers.