Weight loss

I am starting to think I will never lose weight. I can't figure it out. well, maybe I can but I don't want to admit it. I've been running 3x's a week for a few months now, seriously running. Saturday I ran 4 miles, Monday 3 and today 2. This Saturday I will run 4.5 miles. Yet I'm not losing any weight. I am also doing exercise videos.

There are only two reasons for not losing weight, I think they both have something to do with my lack of weight loss . My knees are swelling from all the running, they are really holding a lot of water which I'm sure is some of the fat I have lost. The other option (the one I don't like) is that I am just not eating right. It's not that I eat a ton at meal times or eat bad things really, it's more that I like to night snack. I guess we have also had a lot of snack food in the house lately which I'm sure doesn't help.

I have a goal to look nice by the time my cousin gets married (in July) and yet my stomach still is holding onto the pregnancy fat (from Lexi!) I need some ideas on how to motivate me to not snack, anyone have any?