I've never had a problem getting a partial refill, a bridge so to speak to cover the span waiting for a refill. Talk to your pharmacist, they won't want to be part of the problem if you have a health issue and will give you enough pills to cover you. Plavix is, indeed, as ed34 suggests, a very important medication.
It's certainly better than nothing, but how long until you get more? this is a very important medication.