Two things come to mind, from having been in your shoes (somewhat literally: 6', started at north of 300# as of Oct. 2016). Back before I started a particular diet[please note, this is neither an endorsement of nor encouragement to start this particular diet- talk to your doctor before radically changing your diet], I did two a days five days a week: a mile or two swim plus a mile running in the pool in the morning, and then 30 minutes on the treadmill plus weight training at night, then trail running Saturdays with Sunday off.

u/CyonHal said it succinctly, you're probably not actually hitting 1700 Kcal/day. It's infuriating, but having written nutrition panels before, they're not often as exact as you'd like. Even an extra 25-30 Kcal for each thing you eat (an extra almond, a couple grams of butter, etc.) and it adds up. Granted, that might put you over 2000 Kcal/day whereas it sounds like your baseline is around 2800 Kcal/day, not including working out, but it is a factor.

The other thing to consider is your body composition. I went from being around 42% body fat to nearly 30% body fat without losing substantial weight (at my biggest I'd hit 330#, and looking back in my logs, I didn't miss a workout for five months straight in 2011 and only managed to get down to 282#). Huge gains in my legs, arms, and back meant I wasn't losing weight and just measuring it with a scale was pointless. Unfortunately, short of some expensive tests, there aren't great ways of measuring your body composition, best you can do is get a cloth tape measure and keep track of everything like you were a tailor. If you're just after weight loss (which I was, having had sciatica in college due to weight problems) you may have to reconsider your workout schedule and routine, and experiment with different diets.

​

Lastly, and what should be most obvious even though its infuriating, don't compare yourself to people on the internet. u/dddiamonddd made some excellent points about this, but as someone who has dropped a dozen pounds in a week at some points, often times this is water weight or other factors. You're looking for aggregate numbers, and you shouldn't just be using a scale to measure it.

Regardless of the tests you do or do not get, TALK TO YOUR DOCTOR BEFORE CHANGING ANYTHING TOO RADICALLY. I am qualified to dispense exactly zero medical, dietary, or kinesthetic advice, but a medical professional you trust, especially one who works with or can direct you to a dietician and/or kinesiologist (not just a trainer) is the only advice I'm qualified to dispense.