I am so sorry for the sad experience you just had with losing the foal. That is a shame but as said before me please don't second guess yourself as to what happened. For some unknown reason he was not meant to be. Keep up your faith in minis and don't be discouraged from this frist terrible loss.
I feel so sorry for you and what a pretty colt he was. I have a Playmate daughter. It's never easy to lose a foal after waiting all those months for the arrival.