Steering is very difficult! Help!

Since yesterday morning my steering is very difficult, that is to say when you drive it feels like I would drive without a servo. Could it be that the servo pump can also freeze or is it due to the weather situation here (-17 degrees)? Recently the omi also steers a little bit willingly, I know that it follows every Spurille but that is different, on a straight track comes a ground wave and swoops my omi in an X-libgy direction. What could that be? usammenhang with my situation now that it feels like the servo no longer works? Or has there been some other problem with me, maybe such a kind of steering game … ?? Have no plan of the whole matter, I depend on your help. Mfg Bluebyter