Don't beat yourself up over your friend. Instead, rejoice in her happiness ! Her pregnancy is not a reflection of anything bad you did in your life. Every single one of us have made decisions we aren't too proud of. Those decisions helped to make us who we are today. They should make us reflective. We can't change the past, but we can influence and change the future.
Don't look back, look forward. It sounds like you're already making changes to your life and that's what matters. as the old song goes,"accentuate the positive and eliminate the negative". Give yourself credit for the positive things you do and don't beat yourself up because you're not perfect. No one is perfect. we all have flaws and that's okay.
As you change your eating habits, you'll find that you're going to be seeing lots of changes not just in your cholesterol, but your blood pressure and blood sugar too. Do you know that if your blood pressure were to drop, your doctor would be thrilled even if the scale didn't budge ? Lowering your blood pressure is a huge health benefit.
So, no more regrets. Let's start thinking with a more positive attitude. I think you'll find that when you start thinking positive, you'll start feeling positive too.