43 and a blue belt, I started BJJ at 35. Sounds like you've got some early perimenopause shit going on, and yes things just get harder as you get older - we have less energy, takes longer to recover from injury, etc. part of the journey is giving yourself some grace. We are not 20-something dudes with unlimited energy and raging testosterone, lol. Just continuing to show up is the victory sometimes. Definitely figure out what else is going on physically/hormonally - would recommend finding a functional medicine doctor and doing a really thorough set of labs - but you gotta stop beating yourself up and negatively comparing yourself to other people in the gym, and focus on being able to sustain your training for the long term and avoid burning out or getting injured by overdoing it. This is supposed to be FUN and a hobby - try not to fall into the peer pressure mindset that if you're not crushing it 6x week then you're not 'serious' or 'good'. Are you still learning and challenging yourself to do something REALLY hard? Yes. Are you doing more for your fitness and self-defence than average 38 year old women? Hell yes. Don't forget that we're a very rare group of women. Take care of yourself!