Lost 6 pounds in 3 weeks?

Had a follow up appointment with my OB & apparently I've lost 6 pounds since the last time I was there (3 weeks ago). I'm 17 weeks pregnant. I honestly don't even know how it happened because this has honestly been the laziest month of my pregnancy. I have 0 energy and stay indoors most days. I'm not as active as I was before being pregnant.

Is this a bad thing?