@theo1996
In informal speech verbs (not all) in imperative mood ("Будь счастлив" - "Be happy") can be used to convey conditional mood ("Будь я тут один" - "Had i been here alone").
"Будь" can be used interchangeably with "Был/была/было бы" (independent of grammatical gender). I think it can also be used like "Будь бы", but it sound kinda archaic.