Hi Ganna,
It looks as if you have both diabetes and MS. So do I though I haven't had weakness after eating. I'm more likely to have weakness and shakiness if I go too long without eating.
But there is a diabetes-related weakness after eating as described here:
Reactive hypoglycemia: What causes it? - Mayo Clinic
I wonder if your diabetes control is as good as it should be? Do you have it checked regularly? And have you consulted with a dietitian about your diet? Sometimes just an overload of carbs can cause problems.
Often a symptom that looks as if it's caused by a person's MS is caused by some other condition. You might also want to look into any medicines you're taking and find out what their side effects are.
I hope you can get rid of this problem as I'm sure it's troublesome.