Constant fear

Hello everyone
For a quick information I have developed fears ( also anxiety ) regarding my health since I was 16. I’m now 26.
I’m mentioning that because the situation ( an example from last night ) I’m going to describe is happening all the time in my daily life.
So, we went to play basketball and we were like 10 people however 1 man from those people had traveled to italy about s week ago and it instantly shocked me. The thing is this man ( mutual friend ) was completely healthy despite the fact that there was some cases in that place. Positive news is that It has been a week so far that he was back and he doesn’t have any sumptom.
That’s a good evaluation, even if it can’t be 100% for someone, since it takes a few more days to assure there is no infection. I wasn’t even with any close contact with him nor face to face etc. but we did a typical handshake. As everybody did. Nobody else got so terrified except me.
I got very afraid to be honest and made the worst possible thoughts.
As a measure to be sure, when I got home I used a dettol tissue and then I also cleaned my mobile device.
After that I washed my hands with very hot water and soap. I’ve done this since last night many times as well.
Another thing to mention is that I haven’t touched any part of my head ( mouth eye nose ) at all.
All this things to make sure there is nothing transmitting but apart from that the place was outdoor also.
I’m assuming, first most likely case is that there is no infection to this person and I’ll confirm that in a day or two hearing from him, so if he is perfect then he didn’t transmit anything to anybody else.
Second case lets assume the worst scenario is say he was asymptomatic and got infected but haven’t developed symptom yet, first of all it is not certain he transmits b) isn’t it highly unlikely to transmit something just because of the one second skin contact without any close contact at all? Like haven’t sit next to each other nor get close breath etc. and also after all this cleaning I have done to myself?
I’m mentioning these things because it cant get out of my head and I’m panicking.
Any support or opinion is greatly appreciated.
Thank you very much in advance.