CONGRATS on your 3 pound loss! That is great news!
I completely agree there is so much to learn about managing food. I just returned from a business trip. I had carried a lot of my JC food with me so I could stick with the plan. I did not get all my exercise in that I had planned. Mostly because of a stiff and sore back from all the bag lifting, sitting and running through airports because they kept changing my gate!
As for the exercise; even 10 minutes of exercise 3 times a day adds up. Go for a quick walk around the building or block on break. If you go to the mall or grocery store park farther away to get some additional steps in. If you work in a building with more than one floor take the stairs. Mind you, start with one flight of stairs at a time if your building has more than two stories! Invest in a Pedometer. For the first week just do your normal routine. Write down your steps per day for the first week, add them together and divide by 7 this will give you a daily average. For week number 2, shoot for 500 steps a day more than your first week average. Example: you did 2000 steps a day for week 1, so you would aim for 2500 steps a day on week two. Keep adding 500 steps each week until you hit 10,000 steps a day.
10,000 steps a dayI am a certified personal trainer with the AFAA. Over the past 6 years I have not practiced what I preached and my normal day job got the best of me in the way of stress and I ended up "self medicating at night" meaning I would have 1-4 glasses of wine a day to take the edge off. Seventy pounds later, I decided enough of this nonsense and decided to take my life back in my own control instead of just sleep walking through life. The guy you work with is correct on varying your workouts. Your body will adjust to your workouts the better shape you get in and will become more efficient in burning calories. Which is why many in the health and fitness industry suggestion doing interval training to challenge your system.
To start out though, just get the steps in, start out slow and build a routine. This is the most critical of all. Just getting started and creating a routine. Once the routine is ingrained to where you are working out 4-6 days a week for the next month then you can start changing things up and adding weights, yoga, jump rope

, whatever you enjoy!
Set a goal for yourself: I will work out 3 times this week doing the following exercise ____. My goal is to get _____ minutes in for the week.
Remember, the minutes do not need to be all in the same allotment. 10 minutes at a time to get that heart rate up. Be kind to yourself and patient