So tired!

I am wrapping up week two cold turkey. I had previously used the patch to help when I quit but decided I just wanted the nicotine out of my body as quickly as possible! I have been extremely tired the last two weeks. Like, can not keep my eyes open, dozing off in meetings, unbearable tired. Is this normal? If so, how long does it last? Doesn't really matter as I am not giving up quitting no matter the side effects. Would just like to know if others have experienced this and if I can expect to get some energy back any time soon.