I totally know where you're coming from. Up till about a year or so ago, I was 60 lbs. heavier than when I was in college. For me it was an undiagnosed thyroid condition that started in my 30s. Because of the way I looked, I skipped all my college reunions, even the milestone ones, and I deeply regret it. Now that I'm on Facebook, I can see that my college and high school friends fared no better than I did--either we's fat or we's looking dang old!
As other ASAHers have pointed out, your friends won't mind what you look like. Plus you'll all be there to support one another as you mourn your friend. Can you imagine any one of your group being catty at a time like that? If you can, then that person isn't really your friend in the first place.
But even though that's the logical conclusion, it sure doesn't help when you have to find something flattering to wear or steel yourself to walk into a room for the first time. I sure know how that feels.
Just take a deep breath, seek out your nearest and dearest, look them in the eye with your head held high. I'll bet you'll all be doing way too much hugging to think about what everyone is looking like now.
Also, definitely take note of what noamnety said in your other thread, about cortisol. It is a big influence on weight gain. And if you haven't been able to lose the weight you gaine during your pregnancy, you should have a full hormonal workup (thyroid, pituitary, etc.) to make sure everything's in order there. Pregnancy can send a woman's hormones off the rails permanently, until you get some medical help to straighten it back out. If you want more information, please PM me. I'll be happy to share whatever knowledge I have.