Weird timing of period and intamacy and new to all this

Hello I would just like another opinion on if I should be worried. Some helpful info is sometimes I do get my period later than what it says on the app by a couple days to even a week all the time. Why im worried is I am now intimate with my boyfriend and he finished on my chest area and I may have gotten some on my hand. (Not near my vagina and Let’s assume I did for this story) after 15 minutes or so I, rinsed off in the shower and I used the hand that may have had cum on it to wipe down there. I’m new to this so bare with me but should I be concerned about possibly getting pregnant that way? I have been very stressed about the idea. This was on April 20th and I was supposed to get my period on the 23rd but just got it today I think the 28th. The blood is redder in color but a lighter flow since I have usually pretty heavy flow most of the time but have had lighter in the past. I have been cramping since the 23rd too and it says I ovulated the 9th-15th. So all this happened after the fact. Please help a girl out. Google is stressing me out.