Wow Welcom Jeff! You new baby is beautiful! I am not sure may have missed it but what s her name?
Ten to one odds her meowing is her way of trying to find mom and siblings as if to say okay I give up come out right now! hahahah! Talk to her, cuddle her, pet her, keep her close to you and in time she will unwind and relax and become more confident. Until then enjoy her curiousty and neediness! In no time she will be off exploring the great jungle of your home without you checking in with you!
As for being alone while at school she might be lonely so can you leave a radio something with soft music, low, leave a shirt or artice of clothing out for her to snuggle and cuddle with that has your scent to comfort her! I'd leave her strictly in your room this way no potty accidents because she cna't find her way back to the room/box!