How Do I Accept A Great Month In Business Without Being So Negative?

Since starting my business, I feel like I've been in red alert mode, always either hunting for clients or worrying about producing results for my current clients to make sure they stay happy. I'll be honest its gotten to the point where it feels like I'm always in fight or flight mode when it comes to running my business, and I never really noticed it until this past month when my wife and I went out to dinner.

The dinner was to celebrate what I would call my best month in business so far where we had 3 new clients sign on. Two of which came from referrals from a cleaning company we've worked with in the past and another came from someone we have been speaking to for over a year now and they finally pulled the trigger on trying some SEO for their business. Mix that with that fact that client reports came back all positive without a single complaint and you would imagine I'd be over the moon but I'm not.... In fact it's almost the opposite where I feel everything is so good that there has to be some crash coming soon and as I sat at dinner I couldn't but help but constantly check my phone to look at my text and emails to see if anythign is going on or if anyone has cancelled. I know a lot of people are going to say, " Well, what steak too juicy and lobster too buttery and I get it, but I feel like ever since being a smaller startup, I can't sit back and enjoy the business I've created, even in good months like this. Does anyone relate or have tips?