Sometimes, when we are faced with a difficult decision, there really isn't one choice that is good (although there might be one choice that is less bad than the other).

So, it can be good just to make a decision and stick with it, and have faith that things will work out for the best, and as they are meant to.

If you genuinely feel you made a wrong decision, it is good to talk to someone trustworthy and get their view and see if you should do anything different, but it is better not to keep going over it again and again, as that can feed anxiety. Sometimes part of life is just making a decision and moving on.

If it is possible to change your mind, you can do that, but it is better just to decide once and for all and then set the issue to rest. Going back and forth on a decision can be hurtful to yourself and also to other people involved, such as in family matters, because it keeps them in limbo and from moving on.

Although anxiety is a normal response to difficult situations, it doesn't help yourself or the situation. There are various medical and non-medical ways to try to help with anxiety (which you can read online about). So it is good to try to address that too.