is there any way to tell if someone blocked me on imessage

honestly no reliable way, apple deliberately doesn't tell you. blue with no delivered underneath is what you'd see if you were blocked, but it's also exactly what you see if her phone is off, out of signal or in some focus modes. if you're still seeing nothing after a week or so, and calls go straight to voicemail every time, that leans towards blocked. but you can't know for sure from the phone alone.