If I'm on probation and plead guilty to drunk in public Will the time I served for my first charge be counted?

I live in Virginia and here a drunk in public is a prepayable fine.... If I pay it I know I'll be considered guilty. I'm on UNSUPERVISED probation for a reckless handling of a firearm charge. I spend the night in jail on the drunk in public charge and was released. If I pay the fine and am found guilty am my probation is revoked can they make me serve the whole sentance including the time I already served? I was given 60 days total and am considered to have served 20.(It was cut in half for good behavior) So I'm looking at 40 days the judge suspended. If I am found guilty of a probation violation can he make me serve 60 days even though I technically already served 20 and only have 40 days hanging over my head? And can these be cut in half? Also does anyone even know if a prepayable offense(in VA an offense that does include jail time) can violate parole? Anyone who has any idea I would greatly appreciate your response. Thank you!