You can find a bmr if you google bmr calculators-this is how many calories you need just for your organs and your body to work. Also, yes the protein shake is great for after a workout, also try adding a few carbs after your workout-a banana, rice cake, any type of fruit etc.
Sounds like you are doing alot of strength training and that's good, but incorporate some cardio. How long are your training sessions?
Do the cardio before your strength training, this will keep your heart rate up and your body will continue to burn calories throughout your strength training. Try cardio for 30 minutes atleast 3 times a week. And dont be afraid to mix it up, your body will get tired of doing the same things everyday/week and may stop burning. So, try to mix up your strength exercises as well, like change the order you do them, or try other exercises. 30 min of cardio doesnt have to be just a treadmill or similar, trying running with your dog if you have one, jumping jacks, swimming, roller blading, anything that is going to get your heart rate up.
Tracking calories can be a pain, but try to get into the habit of looking at food labels and serving sizes. livestrong.com is a really good website that has information about nutrition and calculators.
Yes, and 3 meals and 2 snacks a day every 3-4 hours will keep your metabolism going. I am a certified personal fitness trainer and lost about 60 pounds so if you need anything let me know.
P.S. pack a lunch for work! Work is designed to make us fat if your job is not an active one
