Okay, I'm saying all this because you sound like someone I know and care about and this is exactly what I would tell him. So it might sound a little odd in the wording because it's not just generic, but what I'd say to him face to face if he just said to me what you just typed. And if it doesn't pertain to you then fine, but your personality sounds so very similar that I'm going at it the same.
Setting reasonable goals and making allowances if something temporarily changes your course.
That's always different for each person and each goal, whether it's a long or short term goal, even a daily goal. Sometimes life just happens. People get colds, or traffic is bad, or your body made you take five breaks from work in one day when that wasn't part of the plan or someone at home was sick and your boss gets disappointed that you called in, but you have to take care of your family too and yourself if you're too sick to go and be safe while there. You need goals, but just as much, you need to learn that you're not a bad person when life happens. It's part of what makes it all interesting and what it is. Yeah, some people hate that, but let's not get all "Brave New World" here. It wouldn't end well for the ones that don't like anything to ever get messy.
Not allowing others to define how you feel beyond a reasonable point. For example, if you didn't do a decent job, there's not much point in not taking the consequences. However, if you did decent and you know it and your boss or the person next to you is having a bad day, you still might go ahead and (unfairly) accept their criticism if it's not abusive, because that's probably just how you are and it's not my intent or right to say you shouldn't do that, but in your heart, you should not be thinking to yourself that it's your fault. You should be thinking "what is going on in this person's life that they are lashing out at me when I did nothing wrong?" Instead of bringing up feelings that you're not good enough or that somehow it is your fault, try to find compassion for them and realize that it is their problem, not yours. Pray for them. Realize they need it. And pray for yourself. You need it to when you're treated wrong. You're not a sissy to need comfort from the Holy Spirit.
Sometimes, people are their own worst critics, and also very sensitive to perceived criticism. People like that tend to get taken advantage of, then they feel even worse because they feel dumb after, but then tend to feel better about it by telling themselves "I'll act Christian about it and take it as a suffering for Christ." You're allowed to be angry...and sin not. You're allowed to be more cautious and you're allowed to be careful.
With this personality, it's also a good idea to think for a little while before automatically feeling bad over something someone said. Ask yourself a few times if there's another way it could be interpreted. Try to train your brain to always think of the positive interpretation first. (of course sometimes it's just really obvious that it wasn't!)