hrmm... oh... I know what it was! You forgot to take the 3 damage from starting your turn next to the swarm, which immediately dropped your HP to 36 BEFORE you dropped the dwarf and gained the temp hit points. So at that point you had 36 and 6 temp. Then you took 5, dropping it to 36 and 1 temp. Next you took 19 damage, dropping you to 18. Now, at this point you SHOULD have gained the temp hp... but I completely forgot that you had that racial feature. You then took another 17, which took you down to 1 hp. Now, with the addition of the 5 temp hp, you would be a 6. As for reworking the last round... I suppose I could... may take me a while to retrace things back to where they were. When I was writting my post I still saw that you had the swift charge in there, so I think I assumed you used it...
If you really want me to rework the round I will, else we can just push on. I'll leave that up to you and the group, since it could effect their turns.