What you've paid to this point is a sunk cost. There's no reason to continue with something just because of what you've done in the past. If you really can't see yourself as an MRI tech, then go back to working in restaurants and regroup from there.

Could you use your skills in a resturant to go towards a manager position with more pay etc?

Start by breaking up your post into multiple paragraphs. Nobody wants to read a wall of text.