Serious plateau

I’ve been working out consistently for nearly 2 months now and have only lost 5 pounds at the beginning. I still have at least 15 pounds to go but the scale and measurements haven’t budged for over a month. I have been doing the “Sweat” program lifting as heavy as I can, I eat clean 90% of the time, drink at least a gallon of water per day...what am I missing. It’s super discouraging not loosing weight or inches after working so hard. Any advise would be so appreciated.