Spring Harvest VS Work

Well I'm due to go to Spring Harvest on Easter Monday til Friday and I'm not sure now whether I want to go. I have as you know just started a new job and there is really alot going on at the mo and I am really part of it all. I feel at the minute that I should not go spring harvest and stay at work that week as there will be alot that I wont understand when I get back as I will have missed a week at work. The problem I have is that theres no one to take my place and I cant afford to loose £165 its cost me to go. My friends I'm going with have been before and feel that I should still go as they tell me its life changing but I really feel I would now prefer to stay at work that week. I have prayed about it and will continue to do so, I know I should go but why go if you cant be arsed to go and you would prefer to go to work, will it be so life changing if I dont really want to be there?