lifting up concrete slab
There are ways to build up the slab to get it level and then reinforce it.
But if you have to pour footings for enclosing it I would get some advice before you do that since it might require removing part of the pad depending on the local code and any leveling would have been a waste of time and expense.
Plan ahead. It will save you lots of money.
My niece wanted cable in her bedroom and didn't want to bother me with it. She thought that I would have to do a lot of drilling and running of cable. What she didn't know was that when I built the bedroom 15 years ago I put in cable in two places in the room.
I planned ahead. She had cable in 15 minutes.
My idea of a perfect day: No where to go and all day to get there.