Guys and gals! I need your help!! 10 points!?

I've been friends with this guy for about 10 years now and we are turning our friendship into a relationship. We have strong feelings for each other and recently he's been having a difficult time choosing which career to go into and it has him worried. He's been shaky about us, but he says he feels confident to keep our relationship as it is and to take things slow. He's been busy lately prepping to go for his one summer job fighting wild fires in the Nevada desert and he said he would busy lately getting ready since he leaves in a few days. He's been texting me every so often to see how I'm doing, like can be sweet and give me nick names (like "minnie moo") and other times be really cautious and unsure of himself. He says he really appreciates the space I give him which I'm trying to since he's scared about this new job coming up about the wild fires position. Just last night, he texted wanting to know how I was doing and then real quickly told me that he didn't want me to be or feel limited by him to continue to date still. What does that mean?? I asked him if he was seeing another girl and he said no. Should I be worried that he wants to end things with me?