Missing Bb-->Db (above staff)

[jkao1]

Hi, I have been playing the flute for 7 years now. I went on a trip for 3 weeks without playing, and when I came back I had this weird block. The notes Bb --> Db above the staff--I try to play them and it comes out so ugly because 75% of the time I'm hitting the note on the low octave. Any exercises to help me regain? Idk why it's so hard now...