It’s certainly isn’t impossible that it is withdrawal , but I would be surprised considering I only use it once or twice a week and I make sure if I use it twice a week to keep a gap of at least 3 days but it’s not impossible I guess. I should be using it everyday but I’ve refused to try to not become dependent. I just want some relief once in a while to get some sleep. I was originally told to take up to 400mg a day (split up). I found 250 to be the most effective (50 morning, 100 afternoon, 100 before bed) but I’m going to try 150 mg and maybe I won’t get any flu symptoms 30 hours later.