I have anxiety about my friends spending time without me?

I actually have some OCD that brings a lot of anxiety. I used to be a quiet person who didn't hang out with any friends and now I do a lot. I am going to Florida on vacation for a week with my family and my youth group is going to a place to swim and they might do something else during that week. I'm excited about going to Florida but my mind brings in this anxiety that if I don't do everything with my friends that they'll forget about me and not invite me to anything when I get back, then that will cause me to fall back into the quiet stage again. Last time I went on vacation in Florida I was in that quiet stage. Another thing is that at the end of last summer I went through a breakup with a girl and I felt that hanging out with friends made me feel better. When I hang out with friends now I think about the future and how I'll miss all of this for a week. I also play keyboard for our youth band every Wednesday night so another fear that gets in my mind is that will forget about me and replace me with someone else. I want to go to Florida and have a good time with my family but my mind will constantly remind me that I'm missing out on a good time with my friends and that they don't care about me anymore. This anxiety has even had an effect on my family. When my youth group was talking about doing something this summer and they said shortly after camp and my Florida trip is the week after camp. My anxiety fired up and my mind said they'll go during my Florida trip so this anxiety changed me to contact my sister and cancel the Florida trip and go somewhere else another time. It hurt her feelings really bad and after I worked everything out to where I'll go to Florida I went back to normal and realized that it was a bad decision and I wondered why I would do such a thing. This anxiety is getting bad and along with my OCD I always feel terrible. I've been able to feel better for maybe 10 minutes at most but the anxiety keeps coming back. How can I overcome this and be able to enjoy my Florida trip without worrying about my friends? I really need help on this.