today's freakout: weight gain.

Liz
A little background: I was a chunky middle schooler, a cute high schooler, and OBESE all through college and graduate school. I finally got it together, got on Weight Watchers, started exercising, and lost 65 pounds to put me at a healthy 145 and 5'7". When I got pregnant in June, I was about 155, but was running and watching my calories, so I was getting it back under control. Today I'm 23 weeks pregnant, 160.4 pounds, and totally horrified that I'll be a fat person again. I never have the strength to exercise, and I've gained a pound every day for the past week.  
I'm just tired of everyone saying "oh you'll gain what you need to gain!" Scientifically, that's total BS. People who gain 80 pounds when they were healthy to begin with did not, in fact, need to gain 80 pounds. For my body, I would be maxed out to gain 25 pounds. I'd rather have some REAL advice. I worked too hard to be healthy, and am struggling so much right now with fatigue. I need a better system so I can keep me and my baby healthy and happy. 
Any suggestions from people with similar struggles?