Worried about being pregnant

First, she is very unlikely to get pregnant if she is using birth control correctly. the word "correctly" is important and means she isn't missing a day (I am assuming you mean the pill. There are lots of couples that use birth control pills as the only form of birth control. The pill is very reliable.

Second, it is highly unlikely to get pregnant from pre-cum. Pregnancy is not that easy, a lot of things have to happen for a couple to conceive. Generally this is done by ejaculation inside the vagina.

I think you are worrying way too much.

Also (because I am an a responsible troll) you should continue to use a condom to prevent the spread of STDs. You don't need a condom to stop a pregnancy if she is using the birth control pill correctly. But, you still need should use it to be healthy.

I asked her a while ago and she said she misses a day here and there with the pill, and I do think I'm worrying too much but I have anxiety so I do that about everything

It's probably unlikely she's pregnant based on the information you provided. But you can always take a pregnancy test just to be sure. While you can become pregnant if a pill is missed, the chances are slim, as long she remembers to take it right away.

Missing 2-3 pills, however, is a different story.

It wasn't day after day she missed it, its 1 missed every couple weeks, but never 2 or more days in a row

Even if she wasn't taking the pill...

Getting pregnant from precum in saliva on the side of a condom is extremely unlikely... it would be a medical miracle. That isn't how conception works.

Most likely she is not pregnant.

Going forward, maybe try a more long-term contraception method.