Hmm good question there! You know, there’s probably no way to be absolutely sure, but if it were me, I’d take the injection today and load a 3rd day, then start P2 normally tomorrow.
I might also consider how much I had gained loading in the first 2 days so far. If I had gained a lot I might consider not doing the 3rd day load with hCG and just starting P2, but if it was a reasonable amount so far, like 1-3 lbs, I’d inject and do that 3rd day load. It’s getting in your system, you just need that 2nd day of hCG circulating to help things go more smoothly for you as you start P2.
If you want a little further input, you might read my info on doing a 3 day hCG diet load as the principles there may help you make a decision.