I don't come on the forum very often, so I didn't see this when it was first posted Keris! I think there's been good advice in every response.
I am a lady, and closer to 5'7" in height. My first trip underground in eight months will hopefully be next weekend! My caving confidence is rarely high, but it's been much worse in the past than it is now.
There is something to be said for pushing yourself a little on every trip to build confidence, if a particular aspect bothers you. My confidence is related to caving generally rather than specifically climbs, squeezes, ducks etc. I've never tried to make my arms stronger for free climbs, but I've found pilates to increase core strength very useful in all aspects of caving.
I find enjoying myself in a cave without trying to push myself does me a lot of good down the line, though. Makes me remember I like caving and I want to keep doing it. So I pick people I like and trust but also who want the same thing out of the trip as me. The people I pal around with the most in the hut aren't always the ones I go caving with: often I don't actually want to push myself, but sometimes I do. I've employed tactics such as suggesting a cave that is less 'hard' but novel to all companions, or choosing one companion to cave with to practice a particular skill (usually rigging or ladder-work), or doing trips with photographers, or deciding my turn-around point and declaring it beforehand, etc. I guess it helps to have many cavers in the hut to pick from!
At times of low confidence I also do short trips regardless of the distance traveled. I understand the sentiment of "we should do something
worthwhile because we traveled all this way" because I started caving as a student in London myself! What makes a cave worthwhile though? That's different for everyone, but these days I'm pretty simple - I just overall enjoy being in caves. I'm not doing it for the exercise or exploration etc.
On hormones - wonder if anyone else will reply on that? Yeah, frankly my ability to handle stressful situations is way worse at particular points of my menstrual cycle. When is obviously specific to each person. I don't cave alone so those stressful situations includes the pressure of being "social" during caving weekends as well as the actual physical parts. I sleep even more poorly than my typical bad caving sleep, I get so much more emotional, I'll be worried about my body and might be in pain too. It can really suck tbh and I try to complain even more than normal at the annoying parts of caves to direct my frustration at an inanimate object rather than at people - though only my companions can comment on if that works haha. I always take a hotwater bottle to the hut, try to always have painkillers and basically always have all the stuff to deal with it with me even when not due, which makes me feel better about the potential. And in the end nobody usually presses if I change plans last min.
Personally I'd rather not cave on those bad weekends, and sometimes I don't even if I'm at a hut. I accept that sort of sucks too. But even with my best predictions sometimes the timing just doesn't work out that conveniently.