I'm not sure my feelings have ever been out of line with reality. I do not believe I am biologically male, I have just always wished that were the case.
However, in terms of attempts to come to terms with that rather than transition, there were things that I tried and that was part of the discussions I had with medical staff and therapists. Personally, I tried living as a butch and openly lesbian girl/woman. Although it felt better than my attempts to conform to traditional femininity, which were prompted by bullying, it didn't do anything to address the feelings I had in relation to my sex.
The therapist I saw at Tavistock did try to engage in that kind of exploration, but I found her approach very humiliating and invasive. For example, she asked me if I had had any kind of sex, and when I said no she asked me what kind I would like. I said I wouldn't like any, but her argument was that I couldn't know whether I would like being a woman unless I had sex. My mum did ultimately shut that down, as I wasn't yet 16 and so she didn't think it was appropriate, but I still vividly remember how she made me feel to this day. Another exercise she had me do was to look in the mirror, point out the feminine characteristics of my body, and to say positive things about them. I didn't want to acknowledge things like the growth of my breasts or my female genitals, and I didn't feel there was anything positive about that, so I mostly ended up freezing and not saying anything. She did try to elicit why it was I had so much distress about my sex at times, but I've never really known the answer, and I no longer felt comfortable having discussions with her.
Overall I found the whole experience there deeply traumatic and embarrassing, especially as they insisted my mother was in the room during the sessions. The last appointment I went to the woman was particularly pushy and I ended up crying. That was what resulted in me not going back, and my mum arranged for me to see a private doctor when I was 17. I had 3 appointments with him over a year, and after that and the second opinion I needed from a psychiatrist, I was given testosterone as I was 18 by that point.
However, I had a really positive experience with a social worker who provided me one to one support through CAMHs. She supported me for quite a few years until a little after my 18th birthday. She was the first person I confided in. She was always really kind and accepting, and she did ask about things like whether I had a boyfriend/girlfriend etc. but in a sensitive manner. If I wasn't ready to talk about it yet, she would leave it and come back to it another time. She helped me to explore my options, and to think about whether I could be happy living as a gender non-conforming woman. However, she wasn't a specialist in the area and so she had been the one to suggest I be referred to the Tavistock clinic.