I always thought that doing ONLY speech therapy has diminishing returns. For me, any improvement lasted only in the beginning. You need a booster to your confidence also. Pick a skill or habit that has a predictable curve of improvement - for me it was bodybuilding, for you it may be violin practice or piano. It will teach you that your effort matters and has benefits long-term. It will help you realize that stuttering improvement is much the same. For your presentation problem, I would recommend writing your information down on a piece of paper, rereading it a couple of times. Then recite it aloud a couple of times. Then do moc presentations at home a couple of time. This will build confidence and would reduce the need to think on the spot what you want to say during your presentation and instead you will focus on breathing correctly. Dm me, if you want more tips!