At around 10 months he/she should be showing clear indications of being male/female. My guess would say female especially at that age, but It hard to get a concept of her/his size and tail with the pictures posted above. Can you try to post up clear pics and we can better confirm.
He should be fine after a good nights rest. At that young age feed extra small bugs, better to have them eat more smaller ones then to choke on something too big and stop feeding meal worms.
I don't understand the need for an "injection" at that young of age unless it was a life and death issue and on top of that vitamins "injection" would not save its life.
At that age is so hard to tell, I'd say based on the tail I'd give it 70% chance you got a male, but my son says 65% female. Give him/her a few weeks more and it will clearly show signs of a bulge or not in the tail. If you can get clear picture it would be easier to tell.