Reading this and looking at your character's GNB level and gear, I have to wonder a few things about the situation:
-Did you use your cooldowns properly? In XIV, especially in dungeons, knowing how to rotate through your cooldowns is very important to prosper as a tank. Unless you know a big hit is coming and the ability in question won't be off cooldown for it, you should be rotating through your tanking cooldowns when they're needed.
-Is your gear maybe too low level (you're currently level 69 wearing the level 60 gear you get from the GNB quest)?

And something important to note about healer culture in XIV; In XIV the fights are so scripted the need to keep someone at 100% HP at all times incase of random damage-spikes just isn't a thing. A veteran healer will generally heal you when they think you won't survive the next hit. This extends to dungeons as well.