i did 100mg of winstrol as standalone, it was great while running all though i got REALLY TIRED doing the day, needed coffe to boost me into going to the gym! I would say the reason is due to your becomming shutdown, both winstrol and primobolan arent testosterone wich is the main male hormone, therefor deprission while running these drugs can occour!
Many report a superb feeling on test due to it being testesterone.. maybe fire up some HCG during the cycle, or hit some natural test booster, maybe run low dose of test while doing that cycle? Now for you PCT is very much important! hit it hard