Well, then Jacqueline, I would say you are far from ready to return to work. If you are not sleeping well and feeling drained, then you should listen to your body. It's fine being good and active when you want but once your body says 'enough' then hit the recliner and rest.
One important thing you should bear in mind (regular members will have heard this a g'zillion times already) is that you have just had MAJOR surgery and healing from that takes a lot of your body's energy reserves. The skin may looked healed but there is still a LOT of healing to take place in deep, unseen places. Your body cannot cope with both that and your activities at the same time. You need rest and lots of it, to recharge your batteries.
Yes, by all means push yourself, but once your body tells you to, rest. And I think that, by saying what you have, you have quite clearly said you are not yet ready to return to work.