Oh mate, don't beat yourself up. The idea itself sounds solid - the problem is almost never the concept in the first few weeks, it's distribution. I've seen genuinely great products flop purely because no one knew they existed, and average ones take off because the founder threw budget at the right audience.
From a paid social angle, 3 weeks with zero users usually means one of two things: either you're targeting too narrow, or the product messaging doesn't match what people expect from the ad. Have you run even a tiny test budget? Even £50 against a broad interest set can tell you if the hook lands.
What's your current acquisition channel? Or are you relying purely on organic?
