You are not alone, NY! I had to relearn how to ride with flat pedals when we were riding cruiser bikes in Belize and again in Mexico. It is a transition like any other change. And hills definitely make it harder. We were lucky to be riding in flat places; I'm not really sure how to manage an uphill start without clipless. I am sure my 10-year old self knew how!

Anyway, glad you were able to get the changes made and get out for a short ride. I know it must have been good to be on a bike again, even if the situation was not ideal. I am sure the pedals will become easier in time, just like all other things bike-related seem to be.