I might have a problem...

So me and my boyfriend have been together for a year now and we are still very loving and caring towards each other but the only thing that hasn't changed since we first met was the anxiety that I have when I don't hear from him for more than 12 hrs. He is very busy with a full time job and school so I don't always have to know where he is but if he is okay. I have gotten a lot better, but when we were first together i needed and update at least every 4 hours. It's not that I don't trust him, I am just concerned for his safety nowadays almost all the time.  I leap into a panic when I don't hear from him in a day and I was just wondering if anyone else can relate or could give me advice on dealing with this anxiety.