(It seems you were responding to this while I was typing my reply, so it appears you already knew this)
First of all, you've done nice work so far! I wasn't able to press the Down arrow key to store the acorns at the "Home" location, but was still looking good!
If I understand your question correctly, a simple solution would be to add a local variable to your squirrel (AcornCount for example), have that local variable increase by 1 every time it collides with an acorn sprite, then upon that local variable becoming greater than or equal to 10, change the squirrel's animation to your "loaded bag" one. From that point it would be quite simple to reverse the process by resetting that variable to 0 upon completion of a level, etc., to allow it to go back to its original "unfilled" state. This would also serve as the trigger for making the squirrel unable to jump quite as high.
What you will have to decide, however, is artistically which method you would want to use to have the 2nd "bag full" animation. The two ideas that come to mind are simply copying all your animations a 2nd time in whatever image editor you are using and alter the bag to being full, then importing these second sets as "Walk_Full", or "Attack_Full", so that you have something to change them to when the count reaches 10.
The second option would be to redo the animations you have currently where the bag itself is not present, then create 2 static sprites of the bag (one empty, one full). Prior to the variable being 10, have the empty bag sprite either pinned to the back of your squirrel, or have it create the empty bag sprite once, then set its location to the squirrels image point each tick. Once the variable count is equal to or greater than 10, you would only have to change the empty bag sprite to the full bag sprite and repeat its pinning or location tracking.
Long story short for the 2 options i've suggested: make 2 sets of every animation, or modify the 1 set you have and swap out 1 image.
Keep up the good work! (sorry for the lengthy wall of text)