What does it mean when a guy says that you’re so sweet?

Okay so he’s been my friend of 6 years. Around a month ago I made him a box of open when letters as a graduation gift and yesterday he messaged me to tell me that he opened another letter. He said that it was so so sweet. He had no words and also told me that he was having a bad day and a headache but he swore that his headache was gone after reading the letter. I have no idea if he was flirting or not but what if he likes me😭😭
What does it mean when a guy says that you’re so sweet?
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