Pilot reported a Pitot Probe Heat failure during descent in IMC; resulting in loss of air speed data and autopilot pitch down. Pilot regained aircraft control and continued to destination airport for landing.

Narrative

I experienced a Left Pitot heat failure. Relatively new plane for me and I believe I underestimated the situation I was in. I so no other issues at the time so I did not take any corrective action.....And at the time I'm not sure I knew any corrective actions to take. A short time later the Pitot froze up and my airspeed dropped to zero. This caused my autopilot to pitch me down. I disengaged the autopilot and notified ATC of my situation. I quickly found myself off course and altitude low while trying to manage the plane and my airspeed. I have never been in this situation; complete IMC with icing and no primary airspeed indicator. I do believe my steam guage was working but at the time I was focused on using ground speed off the GPS not thinking of the backup. I was getting multiple different CAS messages that I was unfamiliar with and then also lost Cabin pressure at about 14;000 ft. so my anxiety given my situation was elevated. ATC gave me some priority which was very nice of them. I don't believe I deviated a great deal off course but ATC was aware of my deviation and assisting me in getting back on track. I did my best to correct the plane back to proper altitude and course based on my GPS position. Eventually I broke free of the clouds during my descent and could immediately see ZZZ Runway and landed uneventfully. I have since talked with multiple pilots to discover corrective actions that I could have taken in this situation and overall it has been very educational.