Yeah I get that, you are missing that 'connection', I know that feeling - you never know, acquaintenceships can sometimes lead to friendships so maybe by reaching out you may find some deepen. You've been hurt, it's hardly surprising you are nervous of it happening again, but you are older/wiser and will recognise the signs of 'toxic'.

You are right, some running groups can be more friendly than others, I have found the 'affiliated athletic club' types to be more competitive less friendly. Look for mixed ability, and dare I say it plenty of other women (in my experience the guys are usually more competitive!). Wishing you luck