Slow weight loss, what's the problem here?

Hello fittit!

As the title says, I'm having a bit of trouble understanding why after 3 months my progress has been so dismal?

I started at 175 lbs and have dropped to (now around) 160 lbs in the course of the past 3 months. My bodyfat % is likely to be around 15%, and I am 5'8". My level of intensity during workouts has gone up since, but the results have been very slow. I work as a programmer so my job is very sedentary, but after work I go to the gym and run 3 miles at varying speeds (5-7 mph), and follow this up with:

• 100 - 200 core exercises (variable, depends on my energy)
• 2 sets of 10 kettlebell squats
• 2 sets of 15 kettlebell lunges
• I do about 60 pushups and 60 pullups (one set after waking up, one set after work, one set at night)

I've been doing this routine for 2 weeks now, whereas before I was mostly just running (was at 1 mile, now at 3+) and doing core exercises with the usual push/pullups (was at 5 pullups before, now at 20).

My food intake: I figure I should be eating around 2k calories as that enough would be a deficit, but I am eating significantly less as my job forces me to sit on my ass for 9 hrs a day. I'd like to think I eat healthy as I don't consume sugars or sweets, drink my coffee black, eat a fairly healthy lunch, and for dinner I usually have rice with some meat (and veggies). I can elaborate more if you'd like, though I'll say that I seem to have enough energy to finish my workouts. I also drink about 50+oz of water/day.

My history: I used to be very fit last year, but stress caused me to ditch that and I started eating lots of chocolates and snacks. I was 150 lbs with 10% BF and was able to squat 200lbs and deadlift 190lbs. I have been avoiding lifting as I had a shoulder injury from squats last year, but mostly because I'd like to move around after being chairbound. Last year, before I started lifting, I was able to bring myself down to 140 from 170 in 4 months by eating less and running. I'm doing much more now in terms of physical activity, but I've barely seen a difference? I still have this ugly pear-shaped torso with my gut protruding out and I want it to go away :(

What am I doing wrong? I'm posting now because I'm fairly discouraged and feels like I'm not making any progress. Please let me know if you'd like me to elaborate on something. Thank you!

EDIT forgot to mention: I am 22 years old.