Steering problems

A few weeks ago it was raining really hard in my town and I noticed my speedometer was acting weird. It was lagging. I would be stopped and the mph were still not at zero. Now a few weeks later my steering would get stiff and than return to normal. Intermittently I would lose partial power steering. Now my power steering is stiff but not totally gone. (Around this time I heard a loud metallic noise from my rear passenger side wheel well when driving, it was inspected and nothing looked out of place). The steering is only loose(normal) when I start the car and lasts a couple seconds. I am hearing nothing from the pump, my power steering fluid is new(the problem existed before the new fluid as well as after). I also got an alignment and the results showed it was pretty much all good (rear right was -3.00. Cannot change it because of manufacturer). Also, when I make a turn the steering wheel wobbles slowly back to center position.