Can my GF be pregnant from fingering?

[Helpnz]

Ill get straight to the point. I fingered my GF on sunday the 18 (almost a week ago). We were out in the cold so my penis was constantly drying out while she touched me. During one point I touched myself too and noticed a bit of precum on my fingers. I mentioned it to her and also mentioned how quickly it dried in the air. My hand went on to touch her back, pants and inside her pants until i started fingering her again.
Now we are scared because her period has been acting weird. (This is the first time we ever did something such as this).

The following day she had no signs of her period which is ok because her period usually comes around the 26 of the month. But on day 2 after our time together she told me there was a brown discharge/spotting coming from her V. (Implantation bleeding we thought but doesnt that happen after a week of conception?)
The third day the Brown discharge left. She went another whole day without anything coming down until Friday when she said her period came. We were so happy  on Saturday it stopped. She says it was very light and pinkish until the day progressed and she barely had anything. Now nothing is coming down and its already the 25 close to the day when she usually gets her period.
Whats happening? Why is her period acting so strange?
Could she be pregnant?
*important to note * i peed so many times before i touched my precum. It has to be nearly impossible to have had sperm still in my urethra.  
Thanks everyone.

[Kaykayr]

There's a chance she could be pregnant because spotting is one of the symptoms. Although it is very rare to get pregnant from fingering, but it is possible if the finger had sperm.