(NSFW?) Can too much kissing be the cause of feeling sick in the stomach?

An interesting thing happened yesterday, me and my girlfriend spent the afternoon making out, and at the end of it, we both had a sick feeling in our stomachs.

This is somthing that has never happened to me before, but then again, I had never kissed someone for as long as I did yesterday.

There are two possibilities I can think of:

1— She was raised in Asia, I was raised in Spain, she is Asian, I am white, and maybe we are not used to each others germs, as maybe she is immune to all the germs she was exposed to and I am immune to the germs I have been exposed to, but we are not immune to each others germs.

2— Making out for 7 hours makes you feel sick for some reason.

Do any of you have experience with this? what do you think is the cause.

(the sickly feeling is not enough to stop us, it’s not even a minor problem, it’s just something we are both curious about)