that's also true, I can admit. because of my stutter I have a low self esteem. or well, I should rather say: because I've let my stutter have more control over myself than I have control over myself. weird sentence but yeah. there are some tricks to get you started. you can literally just repeat something positive over and over and after some time your brain supports this mindsets. it's like when you're heading "you're so ugly" a lot so you think that you are ugly. this is one example, maybe it's not helpful for you but I would suggest that you dig more into self esteem. it's not like you can not be confident with a stutter, you really can! but especially the first step of something new is the hardest. the second hardest will be to keep going until it's a habit or normal