The headwinds were the single biggest killer we had crossing the country a few years back. We could climb mountains all day, but if we had a headwind it was SO disheartening. Like trying to swim through caramel. I remember in colorado we had a 30mph headwind, up a mountain (on to monarch pass) we reached a turnback and suddenly had about 1/2 a mile of tailwind, i was riding 25mph up the biggest mountain we'd been up... incredible the difference it makes. But you'll make it through and you'll be stronger for it it just requires absolute patience.