4 weeks healing time is general and 'best case scenario' estimate, given just the simple fact that your bone spurs and cartilage will be cut and removed. For bone to completely heal, it can take up to a year, given there is no complications. So, you will feel better in four weeks, but I don't think that you'll realistically be able to get back to work that involves you being this much physically active.
Has the doctor discussed with you anything about special shoes you might need to be wearing? The thing is, you'll have the surgery done on both your feet and I just don't feel they gave you a realistic estimate as to when you'll be able to work,
Wish you all the best,