This is the Birdie Sling by Amy Butler. This bag is HUGE! Perfect for a diaper bag. A project bag or a weekender. It's that big.
Amy is an excellent pattern writer - her directions are clear and so easy to follow. It was like having Amy herself in my sewing room, walking me through each step. It was challenging (too strong a word, maybe) negotiating the pleats but once I got going, the hours flew and I was building a Birdie. So fun. Poor Ken thought he was going to starve to death as I kept on sewing right through the dinner hour.
I think the fabric is by Heather Bailey. The polka dot may be Amy's but the bold exterior print and the stripey interior is definitely Freshcut. I've already procured my next birdie sling fabrics in freshcut. Just you wait.