How to tell if someone with an iPhone blocked you or has their phone on do not disturb?

I have a friend with an iPhone 6. Exact same phone as mine. Well today, I tried to get ahold of her, because I really do need to talk to her. During the day it would ring through, no problems at all. And my texts would go through too. Then I'd say about 5hrs ago when I tried calling her it did ring once and went to voice mail. I knew then I was blocked, but I called again about 20mins later and it went straight to voice mail. No ring or anything. The weird part is that my texts aren't going through anymore. like they will act like it's sending, but it won't say "delivered" under the message. I called using the hide my caller id and the phone call went straight through. but now with her phone it's doing the one ring then voice mail, but my texts still doesn't say delivered. I'm pretty sure she blocked me, but I know at least my texts would have said delivered. I'm new to this whole iPhone thing still.