Visiting prison

I got a mutual friend who wants to date this guy we both know.
Last week he talked to her when i went to her house.
She had him on speaker phone and he wanted to chat with me, i wasnt looking for a dude cuz im still in recovery from a nasty past relationship, and I hate rebound relationships!
Well...my friend, " Sue" was chatting up a storm with
" rob" , and Rob starts asking all kinds of questions about me. I thought nothing of it, they hung up and Sue and I finished hangout time as friends, got our hair and nails done.
Well, two weeks from there, which was my birthday, yesterday by the way, i turned 43..and sue wasnt talking to me on our girls nite out!
Sue seemed mad, upset, distant and angry with me for no apparent reason whatsoever..well about ten minutes after we had my cake and i blew out the candles, she begins to hand me a blue envelope. On the front it says happy birthday.
I thanked sue for the card, ate my cake and we just watched netflix all night after i opene all my gifts..perfume from bath and body works, a scarf with purple sparkles and a new pair of boots for winter. Id left the blue envelope in my back pack and got home this morning to read it. Inside was a card with a dog and a long 6 page letter front and back and a picture of the guy named Rob...
As im reading the letter, this guy had drawn by hand little hearts, butterflies, etc . On the pages and at the bottom asked for my phone number...
I called Sue to check on her after my breakfast, she told me have fun impression on her man..then she hung up.
Im so confused 😕
Why does she think im after him?
It was ONE conversation on her speakerphone, about poetry..she was listening to us chat and i only spoke 12 minutes..am i a jerk if her man likes me too?
I need advice how to repair this friend because im not after her man, i like somebody else whos not a jail bird!