So frustrated

I'm currently 29 years old and I weigh 148 pounds. About 8 years ago (in college), I went from 156 down to 118. Over the years, crept back up, and at 26 I was at 146 pounds. In a fairly unhealthy way (restricted eating, 2-hour workouts 5-6 times per week), I got down to 127. Stopped the ridiculousness of that method, and here I am, at 148. I do not feel my best at this weight. I know I am not "fat" but I do feel that I would like to look the way I did back when I was under 130.
I eat well, I exercise regularly, but I'm starting to wonder if there's more to it than the calories in, calories out mindset that I had when I got down to 127 a few years ago. I'm also wondering if this is becoming so much harder and more scientific because I'm a bit older- or, maybe, I'm just making excuses for myself.

I guess my general questions (and I would appreciate any input) are these:
- Is 145-150 my body's happy weight? Do I need to stop fighting that?
- Does my exercise and diet routine need to drastically change now that I'm a bit older?