Dizziness after sex

So me and my boyfriend was having sex. I was on top riding him for awhile and when I got up I felt super dizzy cause I had to go to the bathroom and grab tissue cause of his nut. So when I got back I could barely walk cause my knees where weak and I felt like I was going to fall. Then I heard ringing in my ears and everything went muffled. I was so scared and I was like I can barely hear all I hear is ringing. What do you guys think happened? Should I get checked?

I feel better now it just never happened before.