Okay dude relax.

1. You did not cum, so there will only be about a 10% chance of her getting pregnant, from your 'other juices'.
2. You didn't penetrate very deeply, so her getting pregnant would have been very difficult.
3. You weren't erect properly, decreases the risk of ejaculation.

I'd say you're pretty safe. Just talk to her about it, make sure she don't get scared and cry rape.