Poor little guy

I left Miley at preschool today for the 1st time. I left him at 8:30am and they called me by 9:15 to come and get him. When I arrived I could hear him screaming before I had even pulled into a parking place. He was officially upset. I asked for advice on what to do next time and they recommended I only leave for 1/2 hour on Friday and slowly increase the time I am gone to help build the trust that every time I leave, I will come back. I then had to get used to the fact that this won't actually provide me with any kind of a break, on the contrary it will be more work, for some time. I am nauseous and filled with doubt. Is this the right thing? It he too young? Do I need that second cup of coffee? hmm