How on earth would it be even possible to get pregnant from this? Paranoid or legitimate concern?

So we were messing around, as per usual, and the basics of what happened were she ended up in nothing but her boyshorts whereas I was wearing boxers and shorts. We didn't have sex, nor did we do anything oral. It was all with our hands. She played with me for a bit but I never actually ejaculated, not once.I think their might have been a bit of pre-ejaculatory fluid. Then it went right back into my pants and I started fingering her, not just rubbing but I also put about one or two fingers into her for only about a minute. Then we also dry-humped for a little bit but she was wearing her boyshorts and I had boxers and basketball shorts on.

That was all that happened.. This happened on the 5th of December and today is the 11th. Today when she woke up she complained of her stomach, head and throat hurting. She said she felt like she wanted to puke. Her last period was on the 8th of November, it lasted about a week (ending on the 15th) and we aren't sure if it's irregular or not since we don't really keep track. I do know it changes weeks, since when I first met her it was the 4th week of the month, then it went to the 1st, back down to the 3rd, and so on and so forth. We both have been concerned about her possibly being pregnant and I know that stress can cause late periods, so I have attempted to tone it down. 

Anyway, I am really scared that something happened, and even more so scared because we didn't actually have sex and I NEVER ejaculated. I also only touched my penis on accident once or twice, nothing major. So the only chance that she could've gotten pregnant is from pre-fluid somehow traveling through 3 layers of clothing, or a small amount on my hand. This isn't the first time we've done things like this, but this is the first time we've paid attention and noticed the other symptoms.

I don't know what the hell to do, I'm scared out of my everloving mind and I really pray that she isn't pregnant and this is just a fluke, but the more I think about it the worse my nervousness tends to get. We're only 17 and I can't let this happen to her at such a young age, she really doesn't deserve it. Any advice would be amazing, and just anything to calm me down or assure me that nothing it going to happen would be phenomenal. Please, please help me.