Within my first year on the tenure-track at a small, liberal-arts focused public university, I managed to land a 3-year, $300k National Science Foundation grant. I also got an article in press and made the papers in Lynchburg, Richmond, and Farmville. Not bad for my first year on the job.
My former research advisor told me not to get used to this level of ease with accomplishment. After all, my turn to hit the wall would come soon enough.
It finally did. Within the span of two days I had TWO articles rejected for publication and one grant go un-funded. I wasn’t really expecting the grant to get funded, though I did have hope. It wasn’t that strong a proposal and I knew it when I submitted it. Can’t be too upset about that. However, one of the papers I considered very strong. Dinged. The other I thought was a shoe-in for publication. Rejected. Receiving the decisions for each paper about a day apart and at the same time as the grant decision made the feeling of complete failure all the more intense.
We pick ourselves up.
I have submitted one of the articles to a slightly lower-tier journal, as recommended by the referees and the other article has been repackaged with a different focus and submitted to another journal. Not getting funding has freed up some time this summer to begin putting together another project that I’m even more excited about.

Two suggestions, based on experience:
1. Get over it;
2. Get used to it.
Working on #1.
#2 may take a few more professional beatings.
Were it possible, I’d loan you my well-worn, somewhat battered, thick skin.
[...] couple of weeks ago I was a bit down because I had two papers rejected and a grant proposal go un-funded. This week, I’m back on [...]