Welcome to the mission! Been there done that! Ok trust me on this, you have to not let it get to you, you will end up in a rubber room with a jacket that buckles from the back.
Everyone above nailed it, Mix up your diet alot, different foods, try some fasting, and flucuate you calories
I would do 3 days at 1100 calories then drop to a day of 500 then bump to 800 - That really worked for me Your body is saying WTF and is trying to conserve its fat = You gotta trick it.
Love the post above Its not the scale, You will get there we all have and it will be the best journey you have ever done