Am I eating too much or too little?

Hey guys.

I'm a big girl (234 lbs and 5' 10'') and I've lost 31 pounds so far (the first 12 pounds I lost before I started tracking my progress on myfitnesspal). My weight loss is very very slow though and I feel like I'm doing something wrong. I eat around 1500-1600 calories per day and work out for an hour a day 5 days a week. I do a mixture of spinning, kickboxing, and weight lifting. My doctor says I should eat 1400 calories or so to lose weight but according to what I've read here, my net calorie count is oftentimes too low (especially on the days I do kickboxing). If it helps, I have an insulin resistance that makes it difficult to lose weight.

My net calorie count ends up being between 700-1200 calories per day (it's usually on the lower side).

Any advice?

A lot of this really depends on your specific goals. I'm assuming that your goal is to lose body fat and maintain or ad a little bit to the lean muscle that you have. (Which has a big positive impact of your metabolism.)
With the information that you supply here: your height, weight, age, and activity level I entered into a calculator that I have found helpful, can be found here (http://www.1percentedge.com/ifcalc/) It is mainly for people who eat on an intermittent fasting schedule but can be useful for calorie and macro nutrient goals, just average the two days together.

So according to the calculator, just to maintain your current body weight with the workouts that you report doing, you would need to eat about 2900 Calories a day.
Since you want to lose weight I set it about 30% below your TDEE (the 2900) your calorie goal comes out to 2000 calories a day.
These are just numbers that I generally like I highly suggest though that you go to the site and play around with the calculator a bit so you can get a feel for how much you need.