sorry you find yourself in this situation. Please look into side effects for Betaseron, and talk this over with your neuro. You mention you didn't feel this way BEFORE your MS diagnosis and Betaseron treatment...so this could very well be a side effect-
"Mental disorders have been observed in patients using Betaseron.
Symptoms included depression, anxiety, emotional lability (mood swings), depersonalization, suicide attempts, and confusion."
My husband had signs of depression and anxiety for years before his MS diagnosis and beginning Copaxone, so we knew his was pre-existing. Sounds like this is all new and scary for you.
Wishing you health and stability-