Welcome @catsandplantmum! 
Every single one of us here has had that feeling. I know people who aren’t recovering from addiction who have it too. It’s actually a pretty common feeling at times in life - so you’re not alone. It’s ok to feel down; life comes in waves, and you just gotta surf them & work on keeping your balance.
You’ve never known sober you either. What scares you more: worrying that you might not measure up for others, or that you might not measure up for yourself?
Addiction is something we usually fall into at a young age because it numbs us and distracts us. After awhile we realize it’s hollow. Addiction is just escape, running away from life. Life is still there when we sober up though.
Life is a beautiful, loving adventure when you’re sober. Yes it takes effort and yes it is very challenging at times (especially in the early days when you’re riding that emotional rollercoaster). But I promise you, I promise, it’s worth it. It’s sooooo much better than it was when we were using.
You’re working on your relationship with yourself. You’re getting to know yourself. Give it time and have faith. You’re a good person, an interesting person, a person who has her own ideas and concerns and curiosities - all valuable in life. Get to know her - she’s interesting
Are you considering joining a sobriety group to help you out? There’s also a lot of good sobriety podcasts and resources to learn from - there’s a good list here:
Welcome again - looking forward to hearing about your journey