Jane,
I think performance anxiety is part of it, but I also think it has something to do with warming up muscles and an eventual reliance on intuition. I've been speaking female for so long that I don't generally concentrate on the mechanics of it anymore, unless I dedicate time to trying to improve it. Following a bit of speaking in a given day, it just seems to click with me. After writing my reply to you earlier and thinking a bit more about it since, there is some stuff I've noticed a voice relationship with:
- Mouth/throat dryness. I some times sleep with my mouth open, and though I don't snore, my throat still becomes incredibly dry. It really gets in the way of my voice some days.
- Having to swap between male and female. I only use my male voice at work, but coming home afterwards always makes it a little difficult to reach the comfort zone of my voice -- as an aside, I am really anxious not to have to deal with this anymore.
- Projection. I seem to have a little more trouble speaking to people with my voice as opposed to using the phone or a headset, and I think that's because having a person in front of me naturally makes me try to project my voice even when it isn't necessary. I've been keeping that in mind and it's gotten a bit better.
- Airflow. I some times neglect to use natural breathing while talking if I'm spontaneously using my voice; I think this is essentially performance anxiety, as you suggested.
I still feel that your pitch is just fine for being in your forties, but I do understand that it's all about how much you like your own voice. If your pitch was higher, I think you'd come off to others as friendly, excitable, energetic -- as opposed to warm, congenial, amiable (your current pitch). Also, your kids wanting to add their favorite emoticons is really cute.