Often, this situations are made easier by not seeing it as a choice between two people.
In other words, leaving one person for another is usually not a good idea period, because we al need downtime between realtionships.
So, don't worry about Joe. Put that on the shelf. If in a couple months you're still interested, then come back to it. And stop processing your current relationship with a possible future one: that's just poor form, no matter how much you want to. talk to a platonic friend who you know will stay that way instead.
For now, cut your losses and Bob's. Five weeks isn't half as long as it feels like to you. It's a blink on the radar. Essentially, you're basically switching gears before you've really even settled into one, so it needn't be a major drama.
So, think about what you want just for you. about if you want to be with Bob anymore or not -- with Joe OUT of the equation, especially since it sounds clear to me you need some single time, period.
If that given, you know you want out, talk to him, being as honest and kind as possible, experessing what it is YOU are feeling about your own headspace and the two of you.
If yo can't do that irrespective of Joe, you've got to deal with that issue yourself, because that's a problem.
Editor and Founder, Scarleteen
My epitaph should read: "She worked herself into this ground."
-- Kay Bailey Hutchinson