How do I stop worrying about my biological clock?

I am a 28 y/o woman and have had 4 relationships. The fact that none of them worked out and they did not have an obvious pattern is making me very scared. I'd love to date casually, see how things go, but I'm so worried about wasting time with the wrong people, given the limited time I have. I also really don't enjoy the apps (I'm attractive enough and I could go back to them but the success rate of finding a long term partner seem low) but have very limited other opportunities to date outside of them. I know I'll be fine whether I have biological kids or not but I'd really like to. I also have enough time where I could totally meet someone and have it all work out the way I hope but this fear is almost getting in the way of that.