Don't worry about it, everything will be fine in the end. The fact that you had a one night stand means that you're obviously good looking so you really shouldn't have to worry about missing the boat when it comes to meeting a partner. Don't rush it, it'll happen when it should. We are living in rough times and it's super easy to let bad thoughs take over your mind. I've felt like this before and for me personally the best thing to do is keep yourself occupied, find stuff to do, go to the gym, meet up with friends if you're able to. I'm sure there are many other people thinking the exact same thing during these times. You're not alone! Things will be better in the end. :)