Does anyone have the problem of just not feeling full?

"Not feeling full" is not the same as "feeling hungry".  It's OK to let yourself feel hunger.  So many of us have never really allowed ourselves to feel hunger.  We are not supposed to eat until we feel full.  We need to retrain ourselves to be satisfied with a smaller portion size. We use the full feeling as an emotional crutch to alleviate boredom or stress.  We use food to celebrate.  We eat until we feel stuffed and we associate that  sensation with comfort.  We need to rethink everything about how we relate to food.

It might help you to strictly eat by the clock for awhile until you learn new habits.  Plan your meals in advance, with set times for eating, and force yourself to stick to that plan.  Nothing bad will happen to you if you force yourself to wait until your next SCHEDULED meal.

rocky513 is right. You need to get used to not being "full". It is actually rather unpleasant to feel full post WLS.

Remember, hunger is not an emergency. (unless you have a medical condition that says otherwise)

And the diet tips of others are also good. I believe in the first year you really need to keep a tight rein on your simple carbs. I hate the stupid crackers and cream of what that docs put on their meal plans.

Finally, just because you are no longer drinking your shakes doesn't really mean you can't benefit from the protein in them. If you really wanted oats on occasion a scoop of vanilla protein powder (of even other flavors) mixed in makes a big difference. It's still a slider food but you are getting some protein in with it at least.

Google theworldaccordingtoeggface for some great recipe ideas.

Someone taught me a motto once, "never hungry, never full'. I always tell that to myself when eating-- the point is to be satisfied-- not necessarily "full". I know-- still not an easy determination to make, but since full and stuffed is a finer line for us a WLS patients-- my goal is always "satisfied". For me feeling full is the feeling of having eaten to much. 

I can't say I've felt genuine hunger yet-- anything I've felt really is not much more than a fleeting sensation. I'm hoping to ride that out as along as possible. If I were in your shoes- weighing and measuring seems like it would be key. 

I've found when I'm "hungry" (not often) it's usually because I'm thirsty.  My body is so used to me ignoring the "thirst" sensation that it has substituted the "hunger" signal which I always answered!  So now, if I feel "hunger" I drink a big glass of water or tea, and if I'm still hungry after 20 minutes, I'll have something high protein.