Definitely go for it, as long as the exercise itself is not causing symptoms to worsen (it sounds like it isn't). In my experience the main symptom to watch out for is 'light-headedness/dizziness'.

I have found exercise incredibly helpful, since I was able to start doing it I think it's really sped up my recovery.

FYI evidence is stronger for aerobic/cardio exercise (eg an exercise bike) than for anaerobic exercise (eg lifting weights) in terms of being beneficial for the brain. However there is some limited evidence for the anaerobic exercise as well.