This is quite common actually, and the fix won't be quick or easy but definitely worth it. Some thoughts:
1. Check out Victor Cheng's "Gravitas" course; or at least, check out some of his blog posts on the topic
2. Do not end your sentences on a higher pitch. We actually had coaching specifically on that point at BCG. Pitch going up makes you tentative; pitch going down inspires trust and confidence
3. Ditch the filler words, which take away from the message. That will probably take you years to get rid of (I am still working on it myself, nearly 8 years after first becoming aware of the issue). Well worth it though
4. Most importantly - slow down the flow and learn to appreciate pauses & silence. If you speak fast, you will sound passionate but won't generate much respect. Listen to how politicians or presenters speak: They will speak slowly, and make you hang on to their every words. I remember a study in France which showed that Presidents spoke slower than when they were ministers or candidates. When you have power, you speak slower; when you speak slower, people think you have power
This is a fascinating topic, and improving here will serve you well throughout your career (and arguably personal life). Good luck