Bbt problems! 😞

bbt problem. I had at least 3 positive opk jan 26-28 . But my temps did not confirm ovulation . In fact my temps are so whacky they go up from high to low evey day . I take it at the same time every morning but I do leave it out on my dresser without the cap on it so it's just bare . It's pretty cold in my room . I'm really starting to think that it's something wrong with it . Have anyone had problems with rite aid purple brand ?? . Last month I had perfect temps but I also kept the cap on it ..