Hi there, My night sweats started just as you explain - first for a few days right before my period, then the began constantly every night. I am 43 now. The sweats started I think 1-2 years ago. It was just this spring when I started sweating profusely every night and when to the Dr. I also had increase in anxiety, nausea and generally felt rubbish most of the time. Couldn't cope! In May I started HRT and the night sweats were the first to go! I think they disappeared within the first couple of weeks.
So if you have symptoms that bother you and interfere with you daily life, I think you shpuld discuss with you doctor. For me the sweats were manageable and did not bother me as much as the constant anxiety, low mood, lack of energy, etc.
Good luck,
Milamam xxxx