Blowjobs

Soooo, I spent this last weekend at my boyfriends house and had a really great time, even though we couldn’t have sex because I was on my period (he’s had bad experiences with period sex before and just doesn’t want to make a mess). However on Sunday morning I could tell he wanted to do stuff, so I tried to help, and he asked if I could give him a blowjob. Now I’ve never given one before and didn’t really know what to do or to expect, but he kinda just told me to try and he just let me do whatever with minimal instruction. I guess it went well cause he ended up coming in my mouth, but afterwards I felt super sick and had to get him to drive me home because I felt like I was gonna throw up. Is this feeling normal? Or is there any way that I can prevent this feeling from happening cause it doesn’t feel great?