Making mistakes is part of being human. Why continue to beat yourself up when most have already put it out of their mind? Connect with your people so you can understand exactly what happened, and maybe even have the chance to make it up by helping someone out!
Just because you can, doesn't mean you should. It's very likely someone who's upset you recently was simply acting under a different understanding as you. Mediate, find your center, respond with balance.
Everyone looses themselves from time to time. It's easy to, with so many options out there. Do a centering meditation then go do something that makes you feel good with people who make you feel good.
If you could only do one thing today to further your projects, which one thing would you choose to do? Remember: being busy doesn't mean being productive, and being too busy in one area might mean other areas are not getting the attention they need.