First of all information about me:
135-137llbs at 166cm (5,5")
Eating 1500 cals for weight loss and slightly cycling carbs to activity level
activity level: Weight training 4 days a week plus commuting by bike an average 25-30 miles a week.
I have been an active person for many years, weight training as well as previous crossfitting.
I have over the past few years averaged at the same weight which is 135-137llbs and every time i have attempted to lose body fat, I've done very well for the first month and lost a few inches as well as a few pounds and then without any changes whatsoever my weight creeps back up to the 135-137llbs that I began with....It is not one of those cases that i get fed up and binge, nope,,nothing changes apart from in one week to the next I have gained all the lost weight.

Additional info: I have been on thyroid meds for 13 years with no problems. Also I have also been having unexplained night sweats for year Been checked for vit D, adrenal, Cortisol, kidney, liver etc...everything normal..

Do I have a set weight and size that my body wants to stay at? or are my hormones out of whack?