HI Jenny, No need to feel lonely, you have lots of friends on this site that you can talk to anytime who all understand exactly what you are going through. What you are feeling is very normal. While you are in treatment you are "fighting the battle" therefore your thoughts are otherwise engaged. It may be the mind's way of telling you its time to move on from here now and get back into life.
You sound like a very strong, independent woman. You need to do what YOU need to do. You are the only person who can judge that. Getting back into work is probably the best thing for you. I have found being idle is the devil's playground where cancer is concerned. All you do is worry and that makes us weak and vulnerable.
Generally, people don't know what to say or how to behave around us. My advice to you is to find one or two good friends you are able to talk to about your cancer - because we all have to offload occasionally. Friends are not as emotionally connected to you as family are and less likely to fire platitudes back at you and try to wrap you in cotton wool.
Suex