As you probably guessed by now, the hot flashes and night sweats are from major hormonal changes. It takes a few weeks for them to really go away - IIRC it took about 3 or 4 weeks for them to stop after I had my Orchi back in 2001. I don't recall the night sweats being as bad when I went off of hormones for my SRS in late 2003 (but then again, it wasn't as major of a hormonal change, as saying bye-bye to the two major producers of testosterone when I had my Orchi [T blockers like spironolactone, etc. are not 100% effective at blocking all male hormones, so an Orchi is like a sudden cessation of ye olde T]).