My Story + need a bit of advice (is stuttering a mental thing?)

My Story + need a bit of advice (is stuttering a mental thing?) Hi, I just feel like sharing my experiences with you guys and Im looking to get some advice. I started stuttering when I was a small kid at the age of 7 after my parents divorce. Things have changed and I didnt really understand what was happening so I formed some kind of anxiety that I was unconscious about because I didnt really understand what happend. I went to a speech therapy that really helped me a lot and built up confidence. I came to the part where the therapist was saying she cant do anything more for me since I never really stuttered anymore when I was at the therapy. Technically, I dont really stutter I just have a hard time to bring out sentences. I often block while speaking. But the weird part is that I dont stutter always. When Im talking to my friends and my girlfriend I normally dont stutter at all. When it comes to some sort of argument then I start to (not in any cases only a few) but even if Im telling a story to my friends I dont stutter. I only stutter when I think about what I am going to say before saying anything because then I will think that I will stutter. So its like a mental disorder I think which really drives me crazy sometimes. I just finished school and now attempted to a pre-college kinda thing for 3 months. The problem is that its an English college but English isnt my mother tongue so I need to think about how to correctly say things before speaking which makes me think that I will stutter so I start to stutter. If I would be speaking in my mother tongue I wouldnt do. Sometimes in class I want to say really good things but I just cant and that makes me feel pretty sad sometimes because I could be really good but I just have a hard time to give long, precisely formed answers. I always beat the stutter before. I have many friends a girlfriend and Im not afraid to talk to strangers anymore and managed to do all that but I feel like the stutter beat me this one time which sometimes makes me feel really really bad. I just want to know how to leave the comfort zone so I can finally beat the stutter since I already have achieved many things but not this. I even had some job interviews and when speaking to the person who is interviewing me I didnt stutter much at all. The funny thing is that its really up to the person Im speaking to. Even if I dont know them it will mostly be fine but when it comes to dominating people I just start to blocking words and I cant do much about it. I would love to hear your storys and advice and how you deal with such situations