Shedding is an indication that the medicine is working. Stopping would not be a good idea. Actually, stopping is probably a really bad idea. There is no way to guarantee the hairs that shed out will grow back if you continue taking the medicine. However you can be reasonably sure that they will probably not grow back if you stop the medication. You need to stay on the medication for a full year to deterimine if it will arrest your hair loss. If you choose to continue taking the medicine, the shedding will stop eventually.
Stick with it and take care,