BBT During Pregnancy

Does anyone still take their BBT now that their pregnant? I'm 5 weeks and started taking it about a week ago because I read it can be useful. However, mine is never constant. It will go from 98 to 94 then to 96. It's all over the place! I read it shouldn't ever be that low when pregnant so it worries me but maybe I'm doing it wrong??? I have no idea. Is anyone else taking theirs?