Im glad you asked this, when i was about to get baptized i was told that right afterwards you feel different. A clear sign that the holy spirit is upon you etc. After i got dunked i felt no different. Then as i was getting dressed, one of the brothers who did the baptizing said over the cubicle doors "can you feel the holy spirit resting upon you brothers?" to which the other brother who had got baptized along with me said enthusiastically "YES!"... i felt no different.
So i went through my JW life assuming that my baptism didn't count, that Jehovah hadn't accepted or recognized my dedication. Years later i asked a very knowledgeable brother who was very approachable and loving to the congregation if he felt different after his baptism. He replied "Yes! But then, i also felt the same right after i was baptized into the Worldwide Church Of God as a youth".
So i understood that that "feeling" the JWs were striving for was nothing more than a placebo. Like when you see faith healers making people feint off a single touch.
P.S. That day only three people, including myself, got baptized. All of us have since left the Watchtower. The man who was in the cubicle who shouted "yes!" was a zealous pioneer but left after his brother went through depression and the elders berated him for his ministry hours going down. The girl who got baptized that day left after her elder father ran off with his 19yo secretary. Both are living happy, fulfilled lives out of the borg.