Too much emotion to paint

So I've been avoiding painting the last few days. I was way excited to finish the bridge painting, but then was way, way too intimidated by the emotion involved with my next painting to get started. Feeling totally heartbroken for our friends that lost their baby a few weeks ago, I volunteered to paint her portrait for them. She took me up on it, wanting to give it to her husband (so if you happen to know who I'm talking about, please don't tell). She sent me a bunch of photos and I've been looking at them daily, feeling a tremendous amount of self-inflicted pressure to do an amazing job. The biggest problem being I start crying every time I look at the photos of this little angel. Other problem being, I have very little experience painting portraits, and a baby seems especially challenging to me, particularly with pretty muted lighting. Anyway, I finally got myself to try a sketch as a first attempt the other night:

And then tonight I got started on a painting. So here's a start. I really want to do a good job here for them. I've always felt it's important to use our talents to bless other people's lives and this is the first time I feel like it really could. To any of you fabulous portraitists, any advice? Please.