A "stomach virus" is almost always actually food poisoning. Examine this possibility. The reality is that you weren't as sick as you thought, and an acute thing like this doesn't affect the chronic progress trend as badly as you think it would. As a secondary observation, I think you'd be much better off at 4000-4500 cal/day if you're actually trying to get to 225, which seems rather conservative for 6'1" to me.
More importantly, this is one more nail in the coffin of "RPE" -- perceptions about what you can do before you've actually done them are almost always inaccurate. I hear that Paul Horn has an interesting story about this, perhaps he'll share.