Behavior issues?

NightSwan

I've just recently tried to be more dominating over him, so he knows I'm the alpha

This probably didn't cause the problem you have now but it can cause aggression problems and since you aren't sure what caused his growling and biting, I'd stop trying to dominate him and learn how to communicate in a way he understands.  I didn't have time to find a lot of articles but the one linked is an excellent one.  There are many more good resources out there if you google 'debunking dominance theory in dogs' or something along those lines. 

http://www.clickersolutions.com/articles/2001/dominance.htm

NightSwan

No, tail between his legs just started. Normally he would be confident. This all started when I tried to scoot him over in my bed so I could lie down, and he started snarling and biting. When I pushed him off my bed (it's just 2 mattress on top of each other, so a very short fall) he just went into the corner of my room, shivering and scared. Whenever I tried to get near enough to put a blanket on him, he would snarl and bite at the blanket.

I am no expert on dachshunds but from what I know they tend to have a more delicate spine than some other breeds due to their conformation. Might it be that you unwillingly and unknowingly hurt him somewhat during the bed episode  ? Does he run around a lot right before you bring him in at night ? Perhaps he makes himself sore and therefore unwilling to be touched. I really hope you can have him checked at the vet soon. In the meantime, I would leash him up before letting him go out and walk around with him until he does what he needs. When time comes to go in, entice him with treats if necessary so that he does not resist (do not drag him in). Avoid picking him up (if you ever do) until you know he is not in pain anywhere.

Thalie

I am no expert on dachshunds but from what I know they tend to have a more delicate spine than some other breeds due to their conformation. Might it be that you unwillingly and unknowingly hurt him somewhat during the bed episode  ? Does he run around a lot right before you bring him in at night ? Perhaps he makes himself sore and therefore unwilling to be touched. I really hope you can have him checked at the vet soon. In the meantime, I would leash him up before letting him go out and walk around with him until he does what he needs. When time comes to go in, entice him with treats if necessary so that he does not resist (do not drag him in). Avoid picking him up (if you ever do) until you know he is not in pain anywhere.

Good catch on this. 

NightSwan

Oh, I hadn't even considered that; that's possible. But I pretty much have to pick him up to carry him upstairs (going up stairs is bad for their back) I guess I could make him sleep outside, but we don't have a dog house and I would feel bad. We're going to the vet this weekend, so hopefully we can find the problem. Does that mean I should stop taking him for walks until we go to the vet? Because I generally take him for a walk every day, and let him run around outside.

What Kitty said .

Bring him in at night; you do not want to leave him outside without supervision. Keep him leashed in the yard. I think you can keep walking him (on leash) but avoid anything that could put added pressure on his spine or joints (jumping up, down, rough turns, etc.). If he is crate-trained, crate when you cannot supervise inside. If not, try to restrain his roaming area (close doors, put baby gates up, whatever).

Let us know what the vet says. Scritches to him and kuddos to you for trying so hard to help him.

NightSwan

He's a dachshund, not a terrier :P but okay, thank you for the advice

Dachshunds are hounds. :) 

JackieG

Dachshunds are hounds. :)