How do I send a message to someone I haven’t talked to in weeks?

Okay so right now Im probably overthinking this but there’s this girl I met on Reddit. We exchange social medias and we used to talk pretty consistently until both of our mental health started to get in the way of communication etc. we went to talking everyday to once in a few weeks and during the time when she would talk to me she said “I like to think of you as a friend and I hope you feel the same as well” and “if you need someone to talk to, I’m here :)”. This was about 2-3 weeks ago and since that talk we haven’t really stayed in touch. Me personally it’s because I’ve been too chicken to send her a message out of fear of sounding dumb.

Then I’m writing what I should say in my notes and then I’m backing out because either I’m over explaining myself, or sounding desperate imo. It’s like in the moment it sounds good and then I’m either editing it or adding more on to what I’ve already said. With that being said I’d like to send a simple message explaining why I’ve been MIA myself and that I’m still very interested in being friends but I’m not sure how often we should keep in touch or how to even start a said friendship. I just don’t know what to say without sounding dumb..