Hi, I Am Taking Lipo 6, A Fat Burner, For

hi, i am taking lipo 6, a fat burner, for almost 2 weeks and i am late on my period. i don't used to be really regular but it have been a long time since my last period. i think the last time was in December or January. last week i took a pregnancy test and it was negative but i don't know what to do next. any suggestion?