Everyone
at one time or other starts doubting about something which is related to them in any way either they love or hates. Being lovable to someone or something also makes him doubt about him because of the care which they have or maybe fear or losing it for they don’t want to lose them for even not forever. For they have seen a lot of other things which don’t seem much likable or to take care of, and also for other personal reasons which they before pointing to compare to their own interests.
It is kind of related to something which you have to or are dealing with right now.
The mind is where you follow anywhere it takes you and it is what follows you. Believe not in yourself but what you really want to do or think because you will be getting there for sure.