One thing that seems to help is his new photo album.
My mom got Jackson his own little baby sassy photo album for Christmas. I put pictures of him in it smiling, laughing, and spending time with family members. Now whenever he is a little teary-eyed I place this little happy book into his lap.
The bendy plastic is great for chewing on and he loves looking at the pictures of himself. Who wouldn't though? He is just too cute!