A couple of questions...
When you called the OBS, where did you feel the runner would have ended up had there been no OBS? 3B or HP?
Was R1 subsequently tagged out during this play?
Did you announce the award?
We're missing a lot of what happened here, but I'll chime in with this first. If R1 had been tagged out prior to reaching the base she would have reached had there been no OBS, you should've killed the play with a "dead ball," and then make your award (3B or HP). If, in your judgment, R1 would have reached HP, but stopped at 3B, then you suspend play and make your award as soon as play has ended.
From the limited info I have here, it sounds like you let the players dictate what happened instead of taking charge and following through with the OBS call. Is there something that I might be missing that could mitigate that assessment?
I don't mean to sound harsh or critical, as I'm sure we've all had those moments at one point in time in all of our careers!