Losing friends

Ever since I became pregnant my best friend and I are definitely not as close... We barely even talk and even though we work in the same building whenever I see her it's just like awkward small talk. I am supposed to be going on vacation with her in a week and I honestly don't even want to go.. I'm in the process of moving and I'll be 27 wks pregnant. Problem is her dad bought my ticket so I am pretty obligated to go. I'm in the process of moving and unsure of what I should do... I could use the vacation I just feel like it will be awkward.