Try to manage gearing better for those uphill sections. When I started riding a couple of months ago I was having issues gearing properly before hills. I learned from reading to usually gear down before you get on the hill and never while youre pushing pressure on your pedals. Pedal down as youre gearing and get yourself in comfortable low gear so you can take on the hills with ease. It wont be easy at first but as you keep going you will have sexy calfs