My Horse Is Slowly Killing Me

I just hit level 35 and have a horse now. I didn't like the color of the one I got so I combined it with a second one and now have a tier 2 black horse. He's beautiful, but every time I mount, I start taking damage. It's about 3-5 health per second and it's not from a mob; I've tried it in the middle of a few different towns. I'm just wondering if this is normal? Am I not a high enough level to ride him? I read somewhere that it could be a negative regen effect but I don't think that's the case. Please help, I really want to adventure with my new horse without dying :)

 

Do you have negative health regen on any items? Double check, this shouldn't be caused by horses.

 

neg health regen items. there are a few items of that range that have neg health regen, i suffered from it too back when i was that lvl

 

I think that was my issue. I changed armor sets and it was fine. But why was it only hurting me when I was on a horse?
I mean it's not an issue anymore now that I know about the armor thing. So thanks for helping me with that.

 

It's still hurting you, when you aren't on your horse it just slowly drains without the damage noise or whatever.