Just feel like running away

As @Julez1958 says, an end-of-active-treatment crisis is not unusual. The regular treatments may not have been fun but they become a norm. I didn’t leave work but many find going back difficult - on one obvious level it’s indicative of everything being back to ‘normal’ but you don’t feel normal, so it’s a disjunction not a reassurance. You mention you’ve tried counselling but there are many types of counsellors and not all are an immediate fit. Someone who can help you articulate what is unsettling you most of all can really help - without that, it’s hard to settle on solutions. A disruptive, life threatening illness upsets a lot of assumptions we might have about our lives. Identifying those changes is the first step to feeling confident and more settled about your future. Best wishes.