Advice please

Hi there

I had a good chat to my manager today. As the other day I handed in my resignation. When she received my letter she was slightly shocked she informed me. I went to discuss with her the areas of interest and what has been bothering me. She listened and she advised me to think about my decision and to let her know if I wanna follow through with resignation.

Also, in the next couple of days, I have a job interview for another unit. I am not sure how it will fair, but how do I tell the interviewer that i am like well in a way I am shopping around for an area that I may think could work out for me. Of course there is an interest to work in the area of where I am getting interviewed but how do I professionally advise that I am keeping my options open to see what this Unit provides and more?

Do I tell my current manager of this Interview that I am going to in the next few days?

Look forward to your reply