Hello there…
I went through a similar situation and after everything I have learnt that
“the reality is that you can’t control how a person feels about you…but you can control your thoughts”…
and I love that you decided to work on your self confidence that is the greatest step and the best step to take…and its okay to feel lonely once in a while because change doesn’t happen in a day…but when you feel lonely,try writing down your thoughts….see what triggers this loneliness..and be aware of everything you are feeling at that time….
letting go of someone is hard but I advice you to keep working on yourself..to feed yourself with positivity (this won’t be easy)…but when a negative thought crosses your mind,try reminding yourself that you are a good person who deserves to be happy…
(I have a reminder on my phone and every day when I wake up the reminder comes and it reads “hey you are beautiful and amazing and today you will be happier than you were yesterday”,.
and after reading that I get out of bed with a positive mindset….

so don’t give up on your journey,keep trying to be the happy,confident person that you want to be and with time you will find someone and if it doesn’t work,remember its not because you were the weak link but because they didn’t work on themselves like you did…

I wish you all the best