It's natural to second guess yourself. The first one is hard. The second one is hard. The third one sucks. I had been on a run of 18 cardiac arrests/18 dead. Finally got one back last week. You know what....the 18th one sucked too.
You will probably second guess yourself for a while. Keep in mind though...if a person is going to die, they are going to die. Really, there isn't a whole heck of a lot we can really do for them if their number is up.
Did you do anything that directly contributed to this patients death? I don't mean fumbling with a tube, or missing an IV on the first or second try, or bagging to fast or to slow, or dropping the stretcher, or anything like that. Is there anything YOU DID, that caused this patients death to happen sooner? Did you push a wrong drug? or Did you not perform you duty (CPR, Tube, AED)? Did you get lost on the way to the hospital and just give up and not drive?
If there is nothing you did that caused this guy to die, then you did fine. Talk about it though. Really it helps. Even after my 9th, 14th...whatever...I still talked a little. By then though it was mostly a few swear words not meant to be heard by children....but it made me feel better.