"that sounds like crap" - now you sound like me talking to myself! 😆 You're definitely in Bb. A cheat for figuring it out is, in most tunes, the very last note in a section (ignoring pickup notes) is the name of the key. The 1 - 4 - 5 chords are your friends (Bb Eb F in this case.) They make the basic frame, that you can optionally jazz up with other chords.