Student first-time founder, 4 months in, swinging between “this will work” and “this is pointless”. How do you deal with it? (I will not promote)

I’m a 20 year old junior at a top engineering college, Tech lead at my uni's Programming Club and I’ve been building a fintech/trading infrastructure product full time for about 4 months, alongside classes (skipping most). What’s going well: Built the whole stack myself in about 10 weeks Placed well in an international trading-agent competition, which is where the idea came from. A couple of established projects in the space want to work with us, and I’m co-organising a session at a major industry conference next week. A "big leagues" investor (accelerator) reached out on campus. The first meeting went pretty well, and the second, with a senior partner, was relatively intense. feedback was “Why is there a need for this? Get more customers.” Fair. I’m a builder, and I’ve spent far more time on the product than on talking to non-tech users. what’s getting to me: For months it’s been a sine curve. Some days I’m sure this will work, and some days it feels pointless. I don’t have an internship or job lined up as a backup. Family worries about me dropping out (I’m not planning to; my college allows credited leave for startup work). Every tough meeting feels like a verdict, even when it’s just feedback. questions i'd like get answers for (but not limited to) How did you handle the emotional swings early on, especially before you had traction? as a technical founder how did you get good at customer discovery? Who did you talk to first, and what did you ask? if you started as students, how did you think about the risk of having no backup and/or about taking a sem drop/break to go attend a cohort? Not promoting anything, and happy to keep the product out of it. I just want to hear from people who’ve been here