Hi, and welcome to this community!
You mentioned you are doing physiotherapy and I think that's great. PT can definitely help people can strength, stability, and flexibility. But, that said, MS can be quite complex and all the exercises in the world may not help a person dealing with, say, foot drop or intermittent muscle weakness and spasms. I think doctors recommend PT because it can help build up one's strength, but it can't fix all issues.
I thought you might find this information on PT and what it can and can't do helpful -- https://multiplesclerosis.net/treatment/faqs-about-physical-therapy-for-ms-patients. I also wanted to share with you two different perspectives on the efficacy of PT. First, here's one member's positive experience with PT -- https://multiplesclerosis.net/living-with-ms/physical-therapy-treat-spasticity . And here's one person's less-than-great experience with PT -- https://multiplesclerosis.net/living-with-ms/physical-therapy-mobility-strength-and-balance. Actually, both pieces are by the same author, showing that sometimes treatments are helpful and sometimes not. Also, this interview with a PT might have some useful information for you -- https://multiplesclerosis.net/guest-expert/physical-therapy-exercise. I do want to note that I have been using the terms PT (physical therapy) and exercise interchangably and there is some difference between the two. Also, when it comes to MS, what works well for one person may not work as well for another. So, exercises may end up really helping you or they may not. They do need to be given some time and consistency for you to make a balanced assessment. And feeling tired or less able to walk after PT is not unusual.
If you have any concerns or doubts, please don't hesitate to talk to your doctor of physical therapist. Being diagnosed with MS can be pretty overwhelming and it's definitely not the time for you to be left alone with medical questions and concerns. Your doctor should be willing to discuss any and all concerns and be open to discussing any treatment options (including exercises) he/she is recommending.
It may takes weeks to see positive results from your exercises and I do hope you do start seeing those improvements!
Best, Erin, Team Member.