Help!

My son (14) has locked himself in his room again. Been 36 hours since I last saw him eat. He won't respond to texts, calls, talking through the door. I had to force my way in (he had the bed against the door) to do a welfare check. He's okay and safe, but refusing to come downstairs, eat...participate. I sat with him on his bed and tried to get something out of him, and just got anger. Not verbal, not physical, but I could feel it and see it on his face. I told him that I loved him, his family love him and that whatever he was struggling we could deal with together. I did say that there are no unacceptable feelings, only unacceptable behaviours, and that locking himself away was unacceptable. Just heaped on the love, then left. I did cry when I was talking to him and I just hope that hasn't made things worse? He was so angry with me! He has done this before, several times, I just don't know what to do if he doesn't emege. to be honest I'm actually better now that I've seen he's angry...mad is much easier to deal with than sad? But I really don't know where to go from here. My anxiety levels are through the roof as he also has an older sister who struggles with anxiety/depression and she's also not great at the moment. It's been a very long night...