NAC side effects?

I started taking NAC this week and I have a headache, worse brain fog and a little more moody and tired. Is this normal and will it go away? Did those who got benefits experience side effects or only saw benefits? I don't know if I should continue, because long COVID is already difficult and these side effects only make things worse. On the other hand, I hope it is transient and will have benefits as the weeks go by;