I think I must have the worst kind of stutter and I don't know what else to do

I think I must have the worst kind of stutter and I don't know what else to do Hello, I'm making this post because I'm a little desperate and don't know what to do, I'm looking for advice, my stuttering isn't the type where I have to repeat the word, it's like sssssssssss-frog, and every day at my work I have to do some reading or presentation to a lot of people and every day I FAIL, every day I feel embarrassed without being able to do a simple reading because I get stuck on the syllables and can't say the rest of the words, but the interesting thing is that in everyday life I don't have any habit of stuttering, I speak normally with people and it seems like I'm cured, but whenever I have to give a presentation or talk to a superior this happens, and I get quite irritated/sad about it, I practice a lot what to say and present it to other people perfectly, but when it comes to actually speaking the words become heavy, I have to make a huge effort to try to speak, I'm lost every day I'm charged with this and they say I have to train more, but I'm always training at home and I present it perfectly. I need tips, I don't know what else to do.