It happens to me only if I let my mind wonder. Which it happens all the time when I got to go per at night but I try to calm my self down a d put my mind on blank.
Btw, I'm 13 wks today too. Yesterday had 12 wk scan and found I was 12wk6. How big did your baby measure? Mine was 6.6cm, hope he/she keeps growing.
Wow, congrats! I have been needing to get up too at those type of hours but luckily I can fall asleep. Are you maybe cold in the night? I found if my feet are cold that I struggle to sleep. Maybe take naps during the day or go to bed earlier, that way you end up getting additional sleep.? I know its not continuous but at least the hours could add up. Im sure things will get better. Apparently in the 2nd trimester having to get up to go to the loo at night will reduce, however, return in 3rd trimester. Good luck to you!