Then later that night he texted me saying he was worried I may be talking to other boys at school or something. I told him how much I loved him and he responded with "I don't know what to think sweetie." Then I didn't hear from him for a day and a half.
You bolluxed that one. You should have said "I'm not interested in anyone but you."
If he needs space, give him space, and maybe text him every other day with a short text that shows you care, without being smothering. Young guys need more space and need more freedom. It's just the way it is. I'm older (early 40s) and I love spending time with my current gf, but I was young once and needed time away from the gf too.
Give him space but MAINTAIN the relationship and keep telling him you are thinking of him, he's special, and you care about him and his needs.
And you didn't even mention sex, which is the #1 important thing to guys that age. Is he getting enough sex? Did he say that he is? Is he happy with the sex? Not enough sex = no relationship.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
(Please note, we give the best advice we can based on the information given in a post. For better advice, please include the age of all romantic partners.)