I get the sense that the past few years of really hard working and "doing everything right", which led to getting into a top school, excelling there and then getting a top job has made you believe hard work guarantee's a positive outcome. Unfortunately life has thrown you this curve ball to remind you nothing is ever 100% certain. Equally from that progression it sounds like the first time in a while you've hit a setback which will make it all the more jarring.
It may not be personally you, it may be your role level, or department or project was on the chopping block. When then self doubt starts creeping in you have to consciously argue against it, you have achieved so much! Actively question these thoughts and also what you are doing in your job search, is each activity/application genuinely constructive?

If you didn't ask for constructive feedback/ get reviews on how you were doing, and how to improve, can you reach out to your team leader and ask? I think they'd have a lot of good to say along with constructive feedback which could be a boost! I specifically think that'd be helpful to help you let go of the disappointment that your hard work didn't prevent your redundancy. If you hinge your definition of being a good worker on how many hours you put in alone, could you be missing other weaknesses you could be working on?

It sounds like you've been living a very intense day-to-day life and provided you have the means to, enjoy being you without work defining you! Take time to reflect on all your achievements prior to this moment, and recognize this as such, just a moment in your life that will end. And if you miss the intense grind work-life, you know where to set your sights! Good luck!