I'm so glad your dad is doing well, that is wonderful.
Since you asked, take a look at how weird this interaction is:
"H is acting really just, I dunno, weird and distant and it's kind of freaking me out. Tonight I got home and we talked a bit but I just felt this huge distance. I finally asked lightly "So watcha thinking?" and he said "Nothing... just stop. I know you're thinking a dozen things and they're all crazy, please just let me stop thinking."
Still not sure what to think about that and frankly too tired to care or figure it out right now. I did respond "Don't worry babe not thinking anything crazy, just trying to ask how you're doing as I know this really freaked me out." H said "yeah" but that was it, started talking about the TV show that was on. "
Think about how weird this interaction is... You feel insecure, you feel distance, so you question him about what he is thinking? He doesn't feel like sharing. Then you defend your questioning of him based on how you were feeling about something else entirely different than what prompted your questioning.
Consider this alternative:
Nikki: "H, wow, I had a rough day. I feel a little weird and disconnected. I'm not sure what that is about -- is there some tension between us or is it just my perception?"
... If you want to show your H you love him, speak his LL, don't try to manage him or his feelings or his reactions.
