Honestly I think it just takes time. When I started seeing my former T, I liked her right away, but it took me SO long to feel comfortable with her. It took me about six months to tell her I had been feeling suicidal (after dodging the question or straight up lying in previous sessions)... I worried that she would be angry with me for not telling her before, but she completely understood and was glad that I finally felt comfortable.
What you're feeling is completely normal. Don't be too hard on yourself. Give yourself time.