What Are The Chances Of STD Transmission Through Inanimate Objects?

hello,
i'm really anxious right now, following an "accident" that happened while I was putting on my sanitary pad.
I had been cleaning my dorm room this morning , using the mop from the maintenance room. I washed my hands obviously and forearms up until my elbow (although it's not like I scraped really carefully, I just rinsed my arms with water and soap while washing my hands but I dont know how through I went.
anyway, around a hour later, I went to the bathroom and took off my pad , then I washed my hands again and went to my room.
I cleaned my hands with hand sanitizer carefully while unpacking my sanitary pad and even had to throw one away cause I felt it touched something.
anyway, I eventually managed to take one out of its packaging and while I was puting it on somehow I felt that the lower part of it touched my forearm. I just ignore that feeling and put it on anyway cause I felt I was clean and it was just a really tiny end-part that touched my arm. But now I'm freaking out cause I feel like maybe my forearm was not that clean after cleaning the room and using the dorm mop and maybe I 'll contract some disease and it will cause infertility. I am soso anxious right now. I feel that even if I take a shower it will arleady be done and I'm already infected.
is there anything I can do' to desinfect and be safe again??