Why a shy guy acts disinterested what I didn wrong?

I have a huge crush on this 37 year old guy since 1 year, he works at the grocery shop so I see him sometimes.
He always been hot and cold:
-sometimes he looks at me in awe; I can see he finds me attractive
-he answers if I try to talk but doesn't initiate EVER
-I added him on Fb first and sent a meme. He laughed and always answers withing minutes if I text, but NEVER initiated a text.

After months I tried to forget about him because I thought he was maybe taken, he looked at me when I tried to IGNORE HIM and I could feel his sad eyes looking at me and trying to catch my attention for weeks.

Then one day he did something nice to me and I sent him a text to say thank you.

I was so confused and scared. I accepted and he said I am such a kind woman.
We went out and I was so nervous. He talked all the time about himself and sports and I was honestly glad because I was so scared even though I tried to stay calm. He also talked about how much he likes to binge drinking during the weekend and about his friends.

At the end of the date he looked nervous and quickly took me home.

He didn't initiate texts, so I did, saying it was nice the date and that I had fun.
He said nothing about the date. Some days after met me and was super charm and tried to help me etc.

I texted him again. I said how much I appreciate him and all the good things I think about him. He said I'm always so kind to him and that he didn't deserve that.
After some days I text saying that he deserves it because I feel safe with him. He again said I'm so kind. We talked a bit and I was so happy he was answering and engaging. I'm always the one saying "I really gotta go to sleep, thank you for your time"). He said "good night, sweet dreams". The last time he was so cold towards me at the store and trying not looking me in the eyes.
Probably I misread the signs and he is in fact rejecting me hoping that I take the hint? Thank you so much, help me!
Why a shy guy acts disinterested what I didn wrong?
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