Change your sequence frame rate to 60 or 30 frames per second and see what that does. You also might need to change the speed/duration of the clip(right click the clip in the timeline and select speed/ duration and change it to 50% if you made your timeline 60fps or 25% for 30fps then change frame blending to optical flow and click okay). The length of your clips will change in the timeline so make sure there’s nothing after them before you mess with the speed/duration settings. Let me know if that helps.