Do you have a save before defeating Laiken, that you can reload and try again? If there was just some weird glitch, trying again may make a difference.
With a save before entering the summoning chamber you can reload and head to the fjords to level (presumably you have finished off everything you can do in Broken Valley and Sentinel Island). After that you may be able to take out the attackers around the battle tower without needing to heal when you return. There is also another dragon skill book you can find in the start of fjords (though that wouldn't make a huge difference).
Even at your current level, you may be able to change your tactics and take out enough of them to finish the fight.
Keep moving; hit target lock for towers/nests and circle around while holding the Fire Breath trigger/key down. If getting in too close causes too much damage, try flying by repeatedly to use Fire Sphere.
On the Xbox, a burst of speed is triggered by the left shoulder button. On the PC this is done by right clicking.
first time dragon help needed pleaseWhy is dragon so hard?