Questions: Guy's Behavior

He was nice to me. He would cover me for breaks without asking when we first met. He initiated every conversation but didn't initiate conversations with me as much as he did with other people. blushes and smiles, with eye contact when talking (but he blushes around everyone) he told me twice that he missed me when i missed work. Avoided looking at me when around each other sometimes, but then would stare at me and smile at me other times. Tried to touch my hand when grabbing the same thing, i think. I felt like there was tension when we were around each other. He was a flirt, but he flirted with everyone. Would text me first and ask to play video games together (online) offered to hug me as an apology (over text) when i mentioned he did something that was rude. At one point, he was super dry over text, but then he started being more effort when texting soon before he quit, making me thing he wanted a friendship outside of work. Called me his friend. When i would talk to him with his friend around, his friend would smirk at us.
Then, It was his last day of work. I didn't want to make him feel bad, so when i was saying bye, i had nothing to say. he said i looked happy, but i told him i wasn't. He offered me his work shirts, and then before i could respond, he drove away really fast. I texted him and told him i would miss him, and i enjoyed working together and to text me anytime. He said that was sweet and "you too" then he started being REALLY dry over text and taking like 3+ hours to send a one word response. I thought he was just busy, but i got a weird vibe. I ignored that feeling until he decided to stop by where we work, and he waited until i got off to stop by. I texted him about it, and he was dry again. The next day, his friend was VERY standoffish around me. My friend told him i missed him and he said he didn't believe her, and then said "that's nice" Did i do something wrong? So confused