Desperately need ya'lls advice!

[Story]

Sorry to hear about your situation. You're In a state I like to call emotional trauma where someone shuts off their feelings do they don't feel the flood of emotions about to hit them.
So some comments
From what you've described you are close with Richard. It's up to you if you want to continue your friendship with him, however you must decide how much you value his friendship first, if you value it a lot you may want to keep your friendship but if you do, you need to have an open discussion with him about this issue. For me, there are 2 red flags being raised, the first part where he tells you G is straight and the second flag is that he knew you liked him and he didn't tell you that he was gay or if it was ok if he dated him.
That seems really backhanded to me. See what he says from that conversation and go from there

For now, try to eat what you can, once the trauma wears off (which it will) and your emotions hit you, you might be depressed and angry for a while after but your appetite will slowly come back too as you work through these emotions
I hope this helps