I have been a week covid free and was asked to start back work monday 7:30am-3:30pm. should i be worried? or should i have waited another week to make sure i wont do myself harm going back to work with physical activity and stairs? any advice?

Hard to say: Covid affects different people through a spectrum from no symptom/features to life threatening. It appears you are passed the point where you pose a risk to others, so returning becomes a self awareness issue. If you are impaired by symptoms to the point you can not focus on your job it may be reasonable to wait. If you are not impaired it should not be a problem.