Is this anxiety or something else?

My boyfriend and I have been together for 3 years. well there was this one time like 2 years ago that he was working in the middle of no where in another city and one day he said he didn't feel good and that he had really bad stomach pains and he couldn't stand the pain anymore. I was worried that maybe something was really wrong but I was just like ok just get some sleep tonight talk to you tomorrow and he said ok that he would call me tomorrow during my lunch time. well he never did. 3 days passed by and he wasn't answering my calls or anything. I was so worried! I thought something had happened to him and I was imagining him lying there dead. Well finally one night he called me saying that he was really sorry and that he had been sleeping a lot lately since he hadn't felt good. I was relived. But every since that one time I freak out like crazy. For example he doesn't reply to his text within a good hour or 2 then I start getting so worried and I feel sick to my stomach, my hands get sweaty, I start walking back in forth like a nervous wreak and I just feel like I am going to pass out and die. Last christmas a few days before, his phone had broke so I had no way of getting a hold of him, unless he called me from a friends phone or something... well I remember I told him the day before to be at my house at 3 pm. 3 o'clock came and went and there was still no sign of him and it's not like I could of called him to see where he was at.. I ran to my room and cried and I felt worried sick. Again, I thought something bad had happened to him. but he finally showed up and I felt 100 percent better. it still happens to me. I am always afraid something is going to happen to him like if he doesn't call/text. I feel like I need help and I am so tired of it! I think it is anxiety but I don't know..