If your team are not able to have at least a short term roadmap for planning your work, then think about assigning points to tickets yourself. Let's say, you think you should be able to do 5 points a day. If you knock out 5 one pointers or one 5 pointer, that's your goal achieved, so you can clock out early if you want to (or carry on if you're in the zone). If you find 5 doesn't fit well (you're working too much or too little for your hours) change the numbering until it's closer.

Keep track of your progress and you should be able to get more of a feel for your own productivity (as well as getting better at estimating tasks).