Hi, y’all. I need help with finding a backpack. It just shouldn’t be this hard!

I’ve had: Tom Bihn Synapse 19–too small, too many pockets, also, for a pack of that price range, I think it should have had strap keepers.
Mountain HardWear Agami–good size, miserably uncomfortable shoulder straps
The North Face Women’s Recon–again, miserably uncomfortable shoulder straps, and it says 31L but there’s no way. It’s just too small for what I need to carry to work every day.

What I carry: 1L Nalgene, a travel coffee mug, a Moleskine, 2 pen bags (I’m a teacher, don’t judge), my lunch, an “everything” bag (bandaids, Tums, Advil, girl stuff, etc.), my Kindle or Nook, sometimes my iPad Mini, a FN size leather notebook, my wallet, a small FAK, 2 sets of keys, a jacket.
Sometimes, I need to carry more, like books for my uni classes, stuff I need to take to work (papers to grade etc.).

I really need it to be 30ish L–and not a fake, compartmentalized 30L either–I actually need all 30L. Decent straps that will allow me to carry a fairly heavy load. Hard wear–I demand a lot from my bags, and for goodness sake, I think it should at least surpass Vera Bradley quality, which is the brand of tote bags I use. I’d prefer to have external water bottle pockets in case my bottle or my travel mug leak.

Thoughts? TIA!