I am reporting back some months later. I now weigh 165 (versus 136 in February). My main carb sources have been rice and white potatoes (sweet potatoes are somewhat exotic and expensive in Holland). I have been on an off on milk. Milk is easy, but not as light on my digestion and mucus, so there's a good reason for paleo to discourage it IMO. My mood has generally stabalized and been more uplifting (or generally more manageable and observable which is actually more important) and I attribute it mostly to nutrition.
If you are looking to gain strength and weight, you must experiment with bananas, sweet potatoes, white potatoes, white rice, brown rice, yams and cassava.
Up until two months ago (most of my gains) I have not eaten too many carbs at all. (below 150g a day). Now I frequently am above it due to energy and muscle recovery. But protein and fat has remained high in my diet, especially after 5pm / 7pm.
Once you find your way, it will work even for a super skinny dude like me (and YOU!)
Oh yeah, train for STRENGTH. 5 reps. 3 sets. (check out starting strength). I have been doing the German Basic Program: (+ Kettlebells)
A: Squat, Bench, Row
B: Deadlift, Pull-up, Press
Train 3 times a week (unless you do additional Sprints/Kettlebells, then do 2 times)