Definitely, completely overthinking this. But anyway...
Earlier, a colleague who I have a bit of a thing for randomly complimented me. It was really sweet, I walked past him, he called me back and said 'just wanted to say you look really nice today! Thought it earlier and didn't want to forget to tell you'
I said thanks at the time obviously. Just texting each other now as we do regularly, would it be weird/AIBU to send a text to just say that the compliment made me smile and that I appreciated it?