I really don't think ketamine is something that should be used for continuous treatment. I've read about people taking large doses of ketamine (and getting into the more mind altering nature of the drug), and having it help remove depression for about a week.
But the problem with ketamine is, you can develop tolerance fairly easily. Not to mention continuous use can cause some very serious bladder problems.
Honestly, I really don't think any drugs are going to fix your depression and anxiety. In my experience, these are issues that you have to deal with yourself, and do so without drugs. There isn't any drug that's going to magically fix your problems, and using drugs will probably just make things worse (whether it's prescription or recreational substances). Eating healthy and exercise go a long way too. But imo the most important thing is to try to develop a more positive perspective on things. And accept the fact that these are just issues you are going to have to deal with to some extent.