I went thru this transition myself...it was difficult, but the fact that you have been working part time, should help both of you. It took me a LONG time to find the perfect caregiver. I tried three daycares, and realized that was not for my daughter, as she was used to running errands, baking, doing home stuff...I finally found a mother who has three girls, 7,9,11, all in school, and she is a home away from home. They do all the things I do with her!!!
In my humble opinion, this would be the best bet for you, as your little one is used to being home, daycare would be a big change!
Also, is there any way, that you can get away with teaching 4 days/wk instead of 5? I work 4 days, then off for 4, which I love. But i'm doing shift work, so I still work 40-48 hrs in those 4 days...but I feel that having 4 days off is important, because I feel completely like a sahm...not sure if that makes sense or not!!!
You will be fine, as will your little one. I almost think it's harder on us...because we know the way we parent and love our little one, and it's difficult to find someone who you trust will treat them with as much respect as you do....it's possible!!!!