Alright I took it at 7 AM and at 1PM I suddendly had a very strong stomach ache, I felt very light-headed and completely confused.
I had to run to the public toilets where I litterally passed out from diarrhea... It might even have been a seizure because I have aches in my neck and side and I believe I twerked while unconscious (I was kinda conscious on the ground thinking to myself "wtf is happening right now")
So yeah, it might have been due to other factors as well (I work in greenhouse where it was almost 40°C, few water, kinda tired)
It's a shame cause I did feel better until that and now I feel weird, I have random tensions in my muscle.
I will try again tomorrow with 1g instead of 2, and maybe persevere for a week 1/2 if the side effects are not too severe as a lot of people said that with NAC you feel worse at the start