I've been stressed about this fingering , what should I do?

Hello

Me and guy had gone to hang out and he started rubbing my vagina . Then he touched his penis and he told he is wet after few minutes he fingered me ... The same day periods started . I'm stressed and don't know what to do .. Will I be pregnant from this ?

No not if you started your period.

Hmmmm... Let's see. If he ejaculated into his hand and then somehow managed to get the ejaculate up into your vagina, there is a theoretical risk of pregnancy. I don't think that study has been done. Now, if I understand you, your talking: he touched his penis, then fingered your wet vagina and you now have your period. I would suggest the chances are pretty slim. Was your period at the time you expected it? If any doubt, wait 3 weeks and do a urine pregnancy test. It should be positive by then, but I think you would be wasting your money.

Could be break through bleeding mistaken for a menstral flow.

How the hell could you be if you started your period. 

Seems pretty aggresive response given you don't know OP's age or what country she is in. Sex ed is sparse beyond words in some country's not to mention anything to do with periods is taboo in many countries as well.