I'd say there's reasons to be worried about going into a medical career, but this isn't quite one of them.
I'm going to talk about this as a previous medical school applicant who is now an engineer/programmer in some of the areas which would make human doctors obsolete. Medicine is viewed as a service provided by skilled professionals and so people will be very hesitant for a long time to allow a robot to take this role, it's a similar situation as for pilots: even though the robot can do a much better job, the service receivers (the patients, and also their families) won't quite understand this and it's difficult to introduce them to the idea. For medicine this is even worse as most people you are treating are going to be even older, and so they have even less understanding of just how good the technology can be in comparison to a human doctor. You might find that your work is enhanced by technology, but you won't be replaced by it.
The real problem is job prospects. The numbers you see for graduate prospects are inflated by being measured at 6 months and so as everyone gets a foundation position, they're automatically near 100%. When you look at post-F2 employment stats, things become much more dire, for last year just 42.6% of medical graduates were in a specialist post within 6 months of completing F2, and the trend is that this number is reducing at a significant rate. In addition, despite the advice is given (at least when I was applying), the medical school you go to has a huge impact on these kind of destination statistics, and just going to any UK medical school doesn't put you on equal footing with every other UK medical school, with one school having a 26.3% rate while another has 70%. The foundation school you go to also has a massive impact, with values as low as 32.4% in some areas compared to 60.9% in others.
If I were to go through applying again (and I didn't end up in engineering) then I would go for nursing. If you're the kind of person who is applying for medicine, let alone one that can get a place, then you can do very well in nursing by going into academic nursing or management. Jobs are abundant, private sector only is a valid option, lots of opportunities to work abroad, earnings end up being pretty similar to a GP except you have an extra couple years of earnings and less loans to pay off. If you still want to become a doctor later on then that will be an option, and you'll have a pretty big advantage over the large majority of other applicants. The downside of nursing is understaffing and the resultant stress and hours, though those still won't necessarily be good as a doctor either.