Near the end?

It's natural to explore domesday mode but as your team has told you, your treatment has been comprehensive to ensure recovery.  I'm 7 years down the line and still get scan anxiety and what if periodically but generally get on with my life .  

For me (and I think for most people!) the CT scan 'to check for spread' is the absolute worst time of all. I had my CT scan early on, before chemo, which I had first. They told me I needed the CT scan, I got it a week later and got the results (all clear) a week after that. Those 2 weeks were the worst of my life. My husband and I talked about things we didn't think we'd need to for many years to come. I made a Will. 

It is a truly awful time and there isn't much to do apart from wait. Of course you can try all the usual things of thinking positively (you have been blasted with chemo!) or not worrying unless you have something to worry about. But the truth is, you will not stop thinking about it until you have the results.

The best I can offer is that we have all been there and understand what it is like to go through it.