Ways to not feel overwhelmed

I am really so overwhelmed, tired and stressed. I have a 4 month old son, I'm changing jobs, I'm in school and my husband's job just transferred him to location which requires him to commute an hour each way (which I know isn't a lot for most but it is for us). Just to things of every day life are getting to me. Like I have really bad self confidence issues. At the moment I work in childcare and I'm able to bring my son with me but at my new job they don't have any infants at the moment so they won't enroll him, and I have to depend on family to watch my son. I worry how all of this will effect him. I stress and wonder if I will be good enough for my new job, I fear I will get there and they will realize what a mistake they made my hiring me...and sometimes I think I should just stay at my crap job with crap hours. I stress about being a good enough mom for my son. I hate change and right now,everything is changing at once. This morning it all came to a boiling point and I balled my eye out as I was trying to head out the door for work. Just looking for advice on how not to be so overwhelmed and stressed.