besides the synchos, it could also be your clutch not dis engaging. Please tell me, does the car shifts normal when the its is not running when you are in park?
just try this, with the car not running, just shift the car to all the gears and see if it the gears go in smoothly or normally. If it does, you have a clutch problem which is gonna happen when you are moving. Its either you have a bad pilot bearing, clutch thats worn, slave cylinder not working or your master cylinder is F up.