Long distance relationship: am I being paranoid?

I'm currently involved in a long distance relationship with someone I care for and love (6 states apart). While we've only been together three months, we hit it off instantly and have been inseparable ever since, well except for the distance. But I wonder if the changes I'm noticing are my own paranoia or just the natural progression of a relationship. At first, we talked all the time...sometimes until 2 or 3 in the morning. There was not a day we weren't on the phone, texting, e-mailing or on the instant messenger. We've made a couple of trips to see each other as well. However, all of a sudden now, we barely talk at all. When we do talk, it's only for a couple of minutes a day and the texts, IMs and e-mails have come to a complete halt. I know cles have begun and I dismissed it as that but it has seemingly gotten worse. I've brought up the subject about the lack of communication only to spark an argument and for nothing to change. I tried to end the relationship but I was told to be patient. I'm told that there is no one else and it's just the combination of work and school. I used to get good-morning phone calls, calls/texts in between cles, during lunches and breaks at work and goodnight calls, etc. There have been weeks where we didn't talk for days. It wouldn't normally be a big deal, but considering this is a long distance relationship communication is important. I don't want to waste my time but because I care, I'm trying to be patient and understanding. Am I just being paranoid or should the decrease in communication be a concern?