Hi there

Well this is definitely a question you need to ask your doctor or even the pharmacist.

In the meantime here are some warnings I found about taking Zoloft with cold or allergy medication: 

"Tell your doctor if you regularly use other medicines that make you sleepy (such as cold or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for seizures or anxiety). They can add to sleepiness caused by sertraline."

So it seems the danger is getting too sleepy.  Not sure what the interactions would be if you took non-drowsy cold medication.  You definitely need to check with your doctor on this.

In addition here is a forum where other patients talk about zoloft and cold meds...seems it is not a good idea to take it with Nyquil especially.

Hope you feel better soon!