If your original sentence came with suspended jail time that is conditional on good behavior for 12months (a likely scenario in your case), and you are convicted of a criminal offense during the 12 months then there is a risk of going to jail on a probabtion violation. Based on what you wrote, jail time sounds likely though it's not certain. I would immediately consult a local attorney who is familiar with the court where you got your marijuana charge. If you want to know whether you were given suspended jail time forthe marijuana charge the go online to the Virginia Supreme Court website and look up "case status" and follow the prompts to find your old case information and sentence.
Luke J Nichols
In addition if your case was a deferred disposition pursuant to 18.2-251 your facing a jail sentence of 30 days and a $500 fine. Get an attorney. You have options with an appeal.