Work vs benefits after brain tumour surgery

Hi, 

I have an injury from brain cancer surgery several years ago and had to quit my job for recovery.  I need to re-mortgage my property but can't get this without another job or receiving benefits. 

I'm reluctant to go back to work because I suffer from fatigue nowadays but I don't want to stay on benefits if I am able to work at a later stage. 

Has anyone been in the same or a similar situation and can advise from their own personal experiences - inc. which benefits they are now on as I'm not sure which to apply for if need be nor whether I will be allowed to go back to work in future if my recovery improves but I'm now receiving benefits?  

Many thanks in advance.

W.