Advice please as worried

Please anyone advise me as I am very worried. I have been self injecting myself for the past 2 years with copaxone but since the past year or so once I have injected I’ve had a reaction to the medication such as tightness in my chest and feeling hot and cannot breathe. I’ve now spoken to my nurse today and she’s advised me that I need to stop taking copaxone and need to start another treatment for the ms as it’s not working and since I’ve been having MRI scans they have found more lesions when it should be stopping or slowing it down. I am very scared which is means my need to do for the medication infusion as it is a stronger medication, can anyone advice me if they have been through this and what I’m I suppose to expect. I actually thought once I started to take the copaxone I when I got diagnosed during the covid time I would be ok but now I’ve gone back to square one again. Please advise me.