Yes in sha Allah your prayer is valid. You should not redo your prayer unless you have done something to invalidate it, otherwise you open the door to waswasa.
http://islamqa.info/en/87749

During prayer I made low mmm sound while thinking about something for a second. I completed my prayer because I have bad waswas that always makes me think my prayer is invalid. But is my prayer valid if I made this sound?

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