Hey there.
I would also agree and say to wait,
The only way to get pregnant from precum is if your partner ejaculated shortly before hand and didnt go to the bathroom in between.
I know that it is hard not to stress out but also stressing out can cause youre period to be off track and not come when you would normally get it.
But like Melanie said wait at least 3 days before your missed period to do anything.
I understand this is not a daily thing but just make sure you be careful.
If you have any questions please feel free to
PM me at anytime!
Take care!
-Chris