I see you already returned your bag, but here is my insight for others who have this dilemma.
I'm 5'2 and have a large soft. It is definitely big for daily use but I find it perfect for work. It holds a book/notebook, lunch container, iPad, cardigan, and my daily items with ease. It does get pretty heavy, but that's fine for transporting to and from the car. I've had the bag for 4-5 months and it has still retained its shape.
I would definitely not use this for weekend, but it is pretty functional for work or even an overnight bag. Definitely think you did the right thing for your lifestyle. I hope a smaller size version works out for you! It really is a beautiful bag.