Losing weight and getting healthy QUESTION

Cake • It's called the American dream because you have to be asleep to believe it.
-- A few months ago, I started to try and lose weight - Im 5ft6 and was 175lb. I started going to the gym three days a week and did mostly cardio. I also walk to and from work, so that's an hour of walking every day I work. I gave up pop and started eating more veggies and less sweets. I did this for a few months and was shocked when I found out I hadn't lost a single pound. 
-- I asked another glow member why I hadn't lost anything and she (basically) suggested that I started all of it too quickly and my body was freaking out and was trying to store all the weight for this sudden burst of activity I was doing. That seemed like the only possible answer. I also talked to my SO about it and he suggested I start counting calories. I've never done that before, so I downloaded an app and have been doing that for two and a half weeks now. 
-- I keep track of calories on paper, but most of it is on an app (I just try and make sure the numbers are right, even if they're just close estimations). It started off shaky - I actually gained another pound after doing it for two days. But two and a half weeks later - currently - I've lost 4.4 pounds. 
-- This is GREAT, but what concerns me is that after looking at my average calorie intake, I'm basically starving myself. I'll usually only get roughly 1,000 a day. So given that, it's obvious why I'm losing weight - but the thing is, I'm NOT eating any less or even much healthier than usual. I eat pizza, pie, candy (still don't drink pop) but for the most part I eat alright. The only thing that's really changed is my breakfast - I make myself a green smoothie. But all in all, I eat when I'm hungry, and I don't eat when I'm not hungry. Yesterday I tried to make sure I ate at LEAST 1,400 calories and even that made me feel like I was getting too full. I mean I'm really not eating any differently or any less than what I was before, and I'm not even doing exercise yet other than my walks to work. 
-- Why the heck am I losing weight?? I'm not complaining, but only eating 1,000 calories a day IS me starving myself even though I'm not hungry x___x;; I try and keep up on my veggies and fruits and I've started drinking tea every morning (like I said, I'm not perfect about what I eat, but I eat OK), but the calorie thing concerns me. I don't want to starve myself and I wanna make sure I'm staying healthy (which you can't do if you're starving). I guess I'm just looking for an explanation or some tips to still get calories without feeling like I'm over eating? Or something? What's wrong with me? X___x