Usually you can get a continuance, however, in the long run, you're looking at that 30 days which was suspended to give you a chance to prove yourself. Unfortunately, you proved yourself - just in the wrong direction.
Yes you can probably get a continuance, especially if it is so you can get a lawyer.
Will you see some jail time? It depends. Which judge do you have? Some judges are more likely to give jail time than others, while some tend to give you the benefit of the doubt, especially if you have no previous drug convictions. Most of the judges will not be pleased to see you back again for a failed drug test, but some get angrier than others and will handle the matter more harshly. There are also a few judges who might want to make sure you have "learned your lesson" and tend to impose jail.
Do you have any other convictions besides this one, including both drug and non-drug related offenses? Repeat customers tend to get harsher sentences. If this is your first and only offense, the judge may impose counseling and/or more strict probation reporting.
If you have further questions or would like to discuss the matter in more detail, feel free to contact me.