M.J.
After we had our first my husband said he was done. We were 22 years old & I kind of blew off what he said about not wanting ANY more kids, but still I went on the pill for the time being. 10 months later we were pregnant again even though I took my pill religously. He was not happy at all at first. He said it wasn't responsible for us to have another baby when we knew we couldn't afford it. He was right that we couldn't afford it, but I was pregnant & terminating was not something I was going to discuss after having been pregnant & bringing one child into the world already. After our daughter was born he said he wanted a vasectomy but I knew I wanted more kids so I told him I would go on the depo shot so as to avoid anything permanent. I stayed on various forms b.c. for the next 8 years until I started having issues and only then after a very long discussion about I-want-more-he-doesn't-want-more did we both agree on a vasectomy.
Telling him was a bit nerve-wracking, but he never acted as though I did it intentionally. We had sex TOGETHER, so no one person can ever be blamed for a pregnancy.
There's nothing you can do now but wait & see if you are or not. Stressing yourself out will only make you later if you're not pregnant.
I do agree with Cheryl that if you both agree you're done with kids then it's time to research something permanent. If you're not, then you need to talk to him about that, but don't expect him to change his mind.