You need more than weeks of abstinence, friend. Ive generally noticed 1-2 months are necessary to recover from all of the awful side effects of caffeine (from drinking a tiny amount of coffee per day - my body is just very sensitive to it). I urge you to try it.
for me, mostly just poor sleep and focus/clarity. It creeps up on you slowly, til you realize youre just in a haze. Once you detox, life is much better.
And, yet, as an addict, i keep convincing myself that I can handle a little bit (like, 6-10 grams daily - which is nothing) and will re-addict myself every few months.
I should say that i have been actually handling 10 grams vastly better lately than i could even 6 grams a few years ago. Not sure what to attribute that to.
I really like coffee - i roast, grind and brew it at home. I should treat it as i do alcohol - only 1 drink, once in a while - but i'll probably remain like this for life...