Dopamine & Sugar Withdrawal

I have joined scholars only recently and have started my protocol of no flour, no sugar and no snacking today.

While I did feel cravings during the day and was flooded with urging thoughts to go and get my favorite foods, at the afternoon I suddenly started to feel also nausea, headache, fatigue, chills, and muscles cramps.

I just cannot believe that it behaves as if I was on some real drug withdrawal.
I am thinking if this is what sugar does to me, it is exactly like drug to my body.

How long should I expect to feel these symptoms?