Low esteem is definitely related to stuttering. Sometimes my days start shitty, sometimes they start good, but however, I've learned that my conversation with people can influence that a lot. If I talk to someone and start stuttering, my self esteem goes to crap and I'll continue like that whole day. If I talk smoothly during first few conversations of the day, rest of the day goes according to that. A lot of it is in your head, and you have to fight through it. Good luck.