Tell me about it. if general physics is a nightmare, ultrasound physics is hell.
I'm currently a DMS student. I had to take a general physics course before applying to the program. It was confusing, but I got through it. Once you are in the program, you'll take additional physics courses, but it is specifically ULTRASOUND physics, which is almost worse than the general class because it's so detailed and extensive. Then you have to take your Physics Board exam (which I am dreading).
I'm almost done with my second quarter of Physics, and I absolutely hate it. But I just do whatever I can to get through it with a decent grade; I use an additional textbook called Understanding Ultrasound Physics by S. Edelman and my classmates get together for study groups. Once you get through it and pass your boards, you are done with physics. It's not something you will directly use in the field (as in thinking back to "what was the formula for determining ___ again??"). The machine actually does most all of that for you, but you have to learn how it all works. Dumb, I know.
So no, don't think you're in the wrong major because of that. I don't know a single person in my program who actually likes and completely understands all of the u/s physics we have to learn. Unfortunately it's just part of it.
So to help you out once you're in the program, I recommend Edelman's book that I mentioned earlier, and if you can find out about Sonography Physics conferences near you, I have heard they are very helpful. Ask for tutoring outside of class, or find a classmate that seems to have a good grasp on the concepts and suggest studying together. Good luck to you, you can do it!