Since I last wrote, Lex has finally found his stride in his "new life." I finally realized that today. Having spent the last few months creating a routine for him and agonizing and stressing over his stress, I came to a point that I wasn't going to put anymore energy into having all my thoughts revolving around how guilty I felt about his life having changed. I think when I stopped doing that, I stopped being so stressed and agitated around him and he stopped feeling pressure from me.
Lex is a super sensitive dog and I strongly believe that he takes on a lot of stress due to my own behavior/feelings. While some things certainly have to do with the toddler, most of his stress was probably due to my own and the pressure I put on him.
I never had to try a prescription drug (in fact, my vet couldn't get what I wanted), but I do have him on an amino acid known for calming stressed dogs called L-Theanine.
We are finally in a happy zone where he knows what to expect most days and I am seeing my happy boy again. In the morning my husband takes him out and feeds him in his crate, then he hangs out in there for a little while and will usually come out and see my daughter and I in the living room after my husband has left for work. Then he usually takes a nap when he sees we aren't doing anything all that exciting and will go back to his crate or lay down behind her rocking chair in her room. We don't have the baby gate up anymore nor do we have to shut any doors. Once my daughter goes down for her noon nap that lasts two hours, he gets super excited and runs to the door because he knows we are going out in the yard to play. We play chuck-it or kick a soccer ball around till he is tired (usually 15 minutes of non-stop play), then go back inside. He drinks water and catches his breath while I do some chores. Then I give him a bone or stuffed kong to eat while I catch up on stuff or take a nap myself, since being 35 weeks pregnant entitles me to a nap! When my daughter wakes up and has a snack and some Elmo time, he usually sits with us then quietly disappears again to come out later when my husband gets home for the night unless we take a walk, pending how cold it is. He waits by the door as soon as he hears the garage and then greets/plays with my husband, goes potty and gets fed again. Once our daughter is asleep, he comes out for playing fetch down the hall or nose work games or just long cuddle and brushing sessions. He now sleeps in the living room cuddled up in a blanket on his bed due to my allergies of him scratching and creating dander all night in our room. He has adjusted quite well to sleeping alone and our relationship is better without me shushing him and telling him to stop scratching all night.
The darkness in our happy light is that life always changes and in about a month we will have a newborn as well. My husband will be home for a few weeks from work helping and Lex may go stay with a friend, but I will have to find a whole new schedule for taking care of his needs and those of two children!