Everything has changed

Everything seems to be changing in my life for the worse at the minute and I don't know why. I work with my brother in law who has recently been promoted to go to Amsterdam for a year and is taking my sister and their son with them. Im so close to my nephew and see him everyday and I have no clue how im going to cope without seeing him. Also my other boss at work has just got a new job and is leaving. But ive realised how much I think im falling for him. Hes in a relationship and is a few years older then me but we get on so well and have banter between us and I cant help but think about him constantly. I don't know how ill cope without seeing him everyday at work. Why is everything suddenly changing for the worst? I feel like I need someone to take my mind off all this but no luck please help should I tell my brother in law I don't want them to go and tell my boss my true feelings? Please help!

it may be for the best,adapt