Seeking Allah’s Help and Guidance During These Waiting Days

As-salamu alaykum - I’m a recent high school grad and I’m really struggling right now. In my final year I was diagnosed with a chronic illness and it affected my attendance a lot, so my final grades aren’t what I had hoped. I’m honestly heartbroken and it’s been an incredibly stressful period. It’s not just the pressure I put on myself; what hurts me a lot is the disappointment I feel from my family. I don’t want to get into everything, but during high school I drifted away from Allah, and my biggest weakness was keeping up my salah. I’m ashamed to admit that. Lately, though, for about a month I’ve been trying to be more consistent with my prayers. University offers come out in a few days and I feel frozen with anxiety and sadness. I’ve never felt like this before. I worry I’ve let my family down. My marks aren’t terrible - I met the minimum - so whether I get an offer depends on how competitive things are. I’ve decided, and been advised, to turn to Allah in this time. People have suggested praying tahajjud, making a nadhr, and performing Salat al-Hajah. I only have a few days and I’m scared the result will be bad. I feel guilty that I’ve come back to Allah most in this period of hardship, and I worry I’m only consistent because the deadline is so close. Essentially, I’d really appreciate clear, practical guidance for the next week. I know this is embarrassing to ask, but please point me toward explanations or simple step-by-step instructions. Tell me which prayers and duas are best to make - I’m looking for the most effective, sincere options I can do in the short time I have. JazakAllahu khairan for any help.