Please tell me that once this paint dries it will match the rest of the wall!?

[getusedtoit]

I have been repairing holes in my walls this week. I put up new sheetrock, then put two coats of mud over the course of two days. This morning I painted on two coats of primer and let them both dry completely before beginning the painting process. Well, I just put on the second coat of paint and it's not matching the rest of the wall! UGGH! Please tell me this is only because the paint isn't completely dry yet!? I'm having a panic attack because I have put sooo much time and money into this project. We are putting the house up for sell in a few months.

Advice? Thanks!
No, the paint is not from the same can but I had the lid from the old can and had it professionally matched....does this matter?