I can understand your frustration. If you are not happy in the course, or feel that you can't complete it, don't worry.
Scuba is a lifetime journey and you don't have to do it all at once.
What I would say is that it's always going to be hard in that shallow pool if you are struggling.
Consider a holiday to somewhere warmer
. Then you could have at least a warm swimming pool as well as the beautiful sea to look forward to for your diving portion of the course, and if you explain your concerns, any worthwhile company will make sure that you get a kind and patient instructor.
Warm water instantly removes a lot of discomfort and stress.
If you are in a group of 7 it's going to be difficult to get the attention and service that you need to get over this "hump".
Don't get discouraged. When I was doing my Divemaster course I ended up in tears at the back of the boat.
I was 58 years old at the time hahahahah. We all can feel devastated by our inability to "grasp" the lessons taught, but they will become second nature if you persevere. (not necessarily with this instructor or company) There are literally thousands of training facilities worldwide. Take your pick.
Otherwise, just keep your head down, keep practicing, and persevere. It will sudenly click.
Don't let them grind you down
You can do it.
Good luck.