I can't drown but the bubble breathe is already 0

I was on my survival world and thought if I could explore underwater so I did it ...but then I let myself near-drown because I'm so bored and thought it would be fun and then I realized that when my bubble breathing is no more my heart only drains at one then back to max what happened it liked punch me but takes time to regenerate my health...I don't have the picture because mojang will thought I'm joking at this bug...I hope Mojang will fix this thank you