Have I massively screwed up?

Heather
It's stinking hot where I live and we've had a heat wave plus tons of rain all summer. I hardly ever go outside with my baby bc of this. Now I'm reading things about vitamin D deficiency and rickets.
He's three months old and hasn't had a lot of sunlight exposure. Have I messed him up? My next doctor visit for him isn't for another month, but I wonder if this warrants a call in😔.