Advice for an entry level engineer

I'm early into my career as an engineer. I graduated 2 years ago with my BS in MechE, I had a job for 2 years with a tech company as a mechanical engineer and now I work for a utilities company as a project engineer in NJ and im dissatisfied with my job and don't enjoy the work after a year of giving it a shot.

I have wanted to go into HVAC or medical device design work as a career but I'm unsure how to get into either of those field. Any advice?