GA pilot reported becoming disoriented while on a visual approach that then entered IMC resulting in an altitude deviation. ATC issued an immediate climb to maintain terrain separation; and issued vectors for an ILS approach; and landed safely.

Narrative

While in descent to OGD; SLC Approach cleared me to 6000 FT; which they said was the reported ceiling and asked whether I had the airport insight. At first; I could not see it and asked for an ILS to Runway 3; circle to land Runway 17. As the controller was providing me with a heading; I saw the airport; informed the controller and was cleared to a visual approach to Runway 17 and asked to switch to OGD Tower. Shortly after; I lost visual contact with the airport and asked OGD Tower if they had radar contact on me. They answered that they did and provided me with a heading and altitude and told me to contact SLC Approach who provided me with a new heading. I was hand flying the plane and briefly got disoriented and was in a slow descent. The Approach Controller repeated the instruction to climb immediately; which I did after engaging the Autopilot at first in altitude hold and then in climb mode. I was then being provided vectors for the ILS to Runway 3; circle to land 17. The approach and landing went without any problems. I made a mistake for not sticking to the original plan to fly the ILS approach rather than asking for the visual approach when I briefly saw the airport. I was task saturated and disoriented for a few seconds.