Recently i had a physical intimacy with my girlfriend and after that i have strange feeling and feel like weird so can it affect the humor of a person..
Yes, it can definitely change a person's behavior. The psychological effect that physical intimacy has on two people is very big. Honestly, one of the biggest things I would suggest would just be to bring it up with that person and ask if everything is ok or just talk it out together. Assumptions won't get you very far.