alot of it also has to do with gearing. your nova probably tops out at 60 gear inches which is very low for flats. my strida only has like 55 gear inches and anyone with gears can easily pass me but I stick with the bike for simplicity and hiding it in my cubicle is nice. But if you gear it up you might have a better time. try a bigger chain ring in the front and maybe change out the rear cassette. It's not the small wheels that's holding you back because moultons have small wheels and they perform even better than full size bikes. Keep up the riding you'll just become better at it, my silly single speed bike is my daily commuter and I can take it to 50km+ charity rides no problems at all and even passing some.