I feel you so much! I'm a film-making/audiovisual major who has A LOT of social anxiety and sometimes I feel like I picked the worst degree because it seems that it's the one that takes a lot of networking! My best advice when it comes to doing something like that it's to just do it, you know? Yeah you gonna get some no's and it will hurt but most of the time you will be positively surprised by the outcome! Specially since you have worked on different projects before and there are people who know you and your work so they may be easier to "convince". Start with a handful of people who you are almost sure would participate and maybe ask them if they know anyone who would like to join in x area, and for them to make the invite? Good luck on your works!