Any help is greatly appreciated, thank you

by Lyndsey

3 days ago I was sitting on the couch with my usually docile JRT, 3 year old female rescue dog, who me and my husband have had for 6 weeks, I wasn't touching her in any way when she turned and bit me in the face, and basically latched on, i had to literally throw her off of me. Since we have had her she has 'nipped' me a few times, but never to this degree, my face is swollen, bruised and covered in cuts, I don't understand what happened and how the situation arose and now do not feel comfortable having her any where near me. I know that she did get abused from the last family that she was with, however has improved immensely since being with us, she had a very nervous temperament, always shaking and cowering and going into 'submissive' positions, which she still does from time to time. My husband is just as confused and he has had dogs all of his life. The thing is she follows me no matter where I'm trying to go, if she is told to do something by another person she wont comply until I give her the go ahead and my husband says she is always looking to me for approval.
I really do not know what to do for the best. We have been trying to find an explanation for this, however are just more at a loss than when we started.
Any help, advice or explanation would be greatly appreciated, thank you in advance.