Hey @mhazard, you are definitely not alone in this feeling, intimacy is raw and vulnerable, which is scary. Sometimes our self-esteem can affect these aspects of our relationship - I've definitetly experienced this. You sound self-aware, which is always the first and most important step so yay!
Some amazing advice has been offered already, I'll try add some new ideas.
In regards to self-esteem and overthinking, keeping a journal with the headings along the line of 'what am I thinking/feeling', 'what is the reality of the situation', 'things I can do to overcome these thoughts/feelings', may be helpful to get things out of your head and logically see it on paper. There are amazing podcasts, youtube videos or books for improving self-esteem, with one small habit making big differences.
Feeling anxiety about pleasing your partner is so normal and valid. Remembering that sex is not perfect but a fun way to explore and build trust with a partner might be helpful. Also focusing on your pleasure and breathing may help you drop out of your head and into the moment! Communicating with your partner is essential, always remain respectful of your boundaries, if you don't feel like it, don't do it.
I hope you find some peace within this soon, we are always here for a chat 🤗
