I choose the path of the Dawngaurd and am on "A New Order" quest. I fast traveled to find the.followers and after I fast traveled I just recived all the perks of a vampire and got the your vampric blood boils message...even though I choose Dawngaurd am i supposed to be a vampire???

There's a Dawnguard subforum, you know that right?
Also you were probably infected by a vampire in battle, when they do that red spell at you that drains health.

You had the disease apparently and yes, you can be a vampire while doing the dawnguard side.

In a word NO! You just got bugged. Restart from an earlier save and try again.

this

cure yourself of vampirism then, go to morthal and ask falion.

A good point, see if you have contracted Sanguine Vampirises before trying again.

I've never been a vampire before though and I never got a message saying i contracted vampirism

Go back to an earlier save, Check in your active effects page to see if you have sanguinaris vampiris, if yes, go to any temple and pray to any god, it will be cleanse.

Yepppers i have it. How did I get it though....through battle?

Only way you CAN get it. It's contracted via a Vampires Drain Life spell, or from an event during Dawnguard where you are actively made a vampire (Vampire Path).

Not to mention, the warning message you get, is the same you would get from recieving a quest reward, too small to take notice, especially in the heat of battle. When dealing with vampires, it's best to check your active effects after you deal with them.

as a human, you can still contract sanguinaris vampiris, specially from the drain spells from vampires (and I guess, serana's too). Your best bet is 1) become a werewolf so you can be inmune, or 2 ) be on the lookout and cure yourself with a cure disease potion or praying to a god.

yes, whenever a vampire uses vampiric drain there is a small percentage that you will contract this disease

Odd i had fought vamps plenty of other times and had never came down with that sickness. Welp forum cloose requested.