Having a path to follow, something you dedicate time consistently, does not mean you will not have doubts.
There will be times when you will question your choices. There will be plenty of alternatives. There will be many reasons why you should change. Actually, there will only be rare occasions when you will feel completely convinced that what you are doing is exactly what you should be doing.
Unless your doubts turn into pain – physical or emotional -, or unless they prove real – with data or facts to support them -, the best thing you can do with it is embrace it. Doubt is part of doing. More often than not, it tells you are on the right path. It can be additional motivation.
You can’t eradicate doubt, so try to make friends with it.