On your goals:
1. It's okay to make mistakes. Pain + reflection = progress.
2. Try to shift your perspective so your sense of worth isn't tied to your work.
3. Anytime you say "I should", "I need to", usually this is sign you are blindly following some sort of cognitive script [0]
The “should” trap is a big one. I found The Work by Byron Katie to be a very effective self-guided method for addressing those thoughts.
I didn't really think about your third bulletpoint, that does make sense.
I think it's also good to be aware when you're lying to yourself. An easy example is how people talk about their gym membership.
"Oh, I would go, but I am so busy with X", or "I am already doing Y, so I don't really need to go". It's always a non-reason, while the true reason is that they just do not see a reason to go.
I don't get why this happens with work, though. I didn't love my job, but I definitely loved the colleagues, and I felt like I didn't do that bad of a job (ofcourse I see this differently now, I was doing a bad job).
In REBT (rational emotive behavioral therapy; a cognitive behavioral therapy focused on rational introspection) the excessive "need" language is identified with "musturbation": https://psycnet.apa.org/doiLanding?doi=10.1037%2Fh0087779
In Buddhism, excessive "need" language is identified with excessive clinging to some aspect of life that behaves contrary to your cravings or your understanding. (Upadana = clinging, tanha = craving, together with its positive and negative forms bhava-tanha and vibhava-tanha, "things must be so," "things must not be so.") The usual cure prescribed is to cure the ignorance that causes these illusions of reality, and/or detach from the clinging that causes your ignorance to inspire suffering (dukkha).
REBT is inspired by a number of philosophies: Stoicism, Buddhism, among others. If this more analytical approach to self-help appeals to you any, I might encourage you to check it out.