Bad mouse lag while playing p99 (sometimes)

[Somekid123]

Where there is lag or for whatever reason ive had it if im holding down right click, slightly move to the left or right my character goes spazzy or is looking down at his feet or above his head, to overcome it I just use the arrow-keys in that situation, but its very rare it happens, usually if im in first person mode with buff graphics infront of me.