Oh, Kelantan! I am soo sorry for all of your worry. I personally am choosing hb this time around for many reasons... one of the reasons being that I feel it is safer. My midwife helped calm a lot of my husband fears (we went into our interview with him having serious doubts, trying to 'rule out' hb was his general reason for being there and we left with him saying he'd actually now prefer I choose a hb!)... Have you talked to your midwife about your worries/concerns this time around? That may help...especially since it sounds like you really loved working with her and you value and trust her opinion. I am sure a conversation with her would somewhat ease your mind.
Your comment about the what if is a tough one. There are what if's in all situations, though. Being a mother is such a huge responsibility and we all have to do our best with the information we have. I think talking with the midwife would be a good starting point...then go on from there.
I don't have much advice (I'm sorry!) but have always found my midwives to be very helpful in easing my worry about ANYTHING!