Yes, there are negative side effects. You should definitely find a way to get your meds. I am paying only 23 dollars for a RX of 30-100mgs. It's worth the money. I have been on zoloft for years now, and I would def not go without it..
Since this is available in generic, it's extremely inexpensive, and any psychiatrist worth his or her salt will call in a refill without having to charge you for it, so you should be able to get a refill.
Perhaps you can see if the pharmacy will sell you a 1 week supply or so to hold you over.
You may very well have some withdrawal effects in the first week. If you have some now you can also try breaking the tablets up and taking a smaller dose each day.