Family misunderstanding?

Last night, I walked into my bedroom and found a plate of cookies and a card addressed to me sitting on my desk. I opened the card and found a letter from my dad. It contained what seemed to be writings from different dates about how he drove my car to work that day and listened to my cd’s a cried for me. There were at least 5 different dates included in the letter about times that he thinks of me and has cried for me.
As I kept reading I became more and more freaked out. My family has always been shaky; my parents still live together but have had a very turbulent relationship for about 11 years now. At the end of the card there was a paragraph about how I should come to his work and visit him this summer. When I read this is immediately thought this was a goodbye letter and he had moved out or something. I freaked out and proceeded to run upstairs at 1am, slamming doors and turning on lights as I went. I yelled to my mom planning to make her explain and as I was yelling my dad sat up from sleeping on the couch, quite alarmed. I started to question him, waving the card in his face. He seemed so defeated, he asked if it was weird and said he just wanted to tell me how he feels.
I retreated to my room, quite embarrassed. Now, I don’t know how to handle the situation other than to run from it. What do I do? How should i talk to him?