Sadly... it isn't the bike. me and my mate did a roll-resistance test side-by side on a slope and my trike kept up with his so it wasn't a binding brake/bearing/flat-tyre etc.
We parked up at a country park for tea & a cake and while I sat enjoying mine he blitzed round the place on my trike with no problems.
It's the rider that has suddenly taken a real turn for the poorer in performance. I'm doomed I tell's ye, Doomed Laddie!
Can ye not fit a electric pedal assisted thingybob, dont be over doing it and make yourself ill.