I came off HRT about 5 weeks ago,same as you, to get a baseline and see what my body does naturally as I had been having excessive bleeding on HRT. I'm 41 and been on it for 2 1/2 years.
I've had the month from hell, headaches, aching back, neck, pins and needles in feet, unable to kneel - just feeling old and aching all the time. not to mention memory loss, lack of sharpness and insomnia!
I started back on the HRT 2 days ago and feel better already. Maybe it's just psychological but I can feel a definite improvement so just shows how debilitating it can be to come off HRT and the resultant drop in oestrogen.
Hope you feel better soon