How long do you need to sit for a clot to form?

I know this post comes from a bit of anxiety and that’s being addressed.

I know the question has many variables to think about to give a decent answer. I have a clot worry. Yesterday for work I was on standby and during that time I fell asleep in my truck for about two hours. Maybe a little more, maybe a little less. I’m just curious if that’s enough time for a clot worry to be justified.

Also a little back history. In 2021 I got Covid. The week following a negative result I drove for training for work. About a two hour drive. I moved my legs around a bit during the drive. Two days after the drive I ended up going to a clinic for leg pain. Was given an ultrasound and told I have a clot and was put on xarelto. A month after I was given another ultrasound and the clot had disappeared and I was taken off the xarelto.

I mention that to say that I know having a previous clot can make you more susceptible to another one. Though I’m not convinced I really had one. By that I mean I was never told if it was a DVT or an SVT. They also gave me an option to not take a blood thinner at the time which makes me lean towards an SVT. That and the fact it was gone in the follow up ultrasound. My PCP could never get info from the clinic to confirm.

TLDR: Fell asleep in drivers seat and worried if two hours is long enough for a clot to form.