What to do....

So I think I figured out why I wasn't losing weight the past two months... I wasn't eating enough calories (and too many of those calories were sugar-based) plus I wasn't exercising. So this past week, I've been trying to eat healthier and closer to my goal, although most of the time I'm under a bit. That's ok, though, because I'm a firm believer that we always underestimate how many calories we really take in each day. I don't measure every ounce of food, it's mostly guestimates, and I'm sure I take in more than I think. Anyway, I also started exercising, and of course, my daily calorie goal went up, which made it even more difficult to meet. (Most days, anyway. I had one or two bad days when I didn't exercise and had a picnic or was out all night and had to grab a drive through dinner, and ended up way OVER my daily goal.) But my main question is, on days like today, when I'm just not all that hungry and I've eaten foods that kept me feeling pretty full... what do I do when I'm still wayyy under my calorie goal? I know that if I don't take in enough calories, I won't lose the weight. But should I really FORCE myself to eat when I'm not hungry at all?? Or do I just eat something not all that healthy for me that has some extra calories, like a slice of pie?? (please... someone tell me to eat the pie...)
But really... It's so hard to believe that I should force my calorie intake up in order to lose weight... I guess I'm just still not sure if I'm doing the right things and eating the right way. Wednesday will tell, when I weigh in after my first week gettin serious... but the suspense is killin me!! I'll be so discouraged if I don't lose at LEAST a pound. Although, I will also admit, I'm not doing a "hardcore DIET" per-se. I'm trying to do the lifestyle change thing, so that I can maintain it for the rest of my life. I don't want to forbid myself from enjoying a slice of strawberry pie with the family at Sunday dinner, but I just need to learn to limit myself. And maybe NOT take home all the left over cupcakes and eat one a day for 4 days. Hey, we can't become perfect overnight.