need advice on trumpet playing

hi I'm currently in my mariachi program at school and for the last month and a half I've been struggling a lot with playing after coming back from a semester break from the program I've been struggling with getting my notes right as well as buzzing/ even making a sounds I've tried taking bigger breaths and adjusting my ombiture and tried a different mouth picec (currently playing with a 7C) but I haven't been able to play like I did the year before and when I do manage to play it can barely be heard, I've been playing for around 5 yeas and never had this happen before any advise would be greatly appreciated

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