Got a call to interview for my dream job AFTER already starting my new job :(

As a last semester nursing student I was applying to whatever position I could. I've always been one of those who wanted to work in OB. It was the subject area I succeeded the most in and it is just simply my passion. I had precepted on a medical floor of a facility my last semester and put my application in because I figured it would give me a leg up. I interviewed and it went well and did not hear any news for a really long time. I was getting discouraged so I started applying elsewhere, for any position that interested me. I saw a position on OB in a facility that is probably 45 min. to an hour away. Never dreamed I'd get a call back, but I did!!! Only, it was on my second day of orientation (yesterday) of my new job on the medical floor that I first interviewed for. I know its just an interview but Im so very disappointed. This could've been my chance, instead I feel obligated and stuck where I'm at. This is very frustrating. I'm gonna have to call the manager back and let her know I'm already employed which is gonna suck even more!! JUST MY LUCK!
Heck no! Take that interview and get your job!!!! Life is too short and your career is too valuable to sart down a path you don't want to be on! You can call the manager and tell her you are working just so she/he will know you have to accommodate that when scheduling the interview but don't give up that job!!!!!!!Please keep us updated on what happens!

Go interview and see where it goes. You are in no way obligated to stay where you are at and if the hospital decided to cut you they would have no qualms about it. Go to the interview, keep going to your current job and see where the interview leads. It may or may not work out and you might find out after interviewing that you are not interested. See what they offer you. Ask to shadow. But don't mention it to anyone at work if it doesnt work out, no harm no foul stay put where you are.Go after your dream!!!