I DONT KNOW WHAT TO DO!!!

My Bestfriend recently told me he has strong feelings for me. I'm not the kind of girl that believes in love but I told him I have strong feelings for him too! Ever since I told him, he's been with me 24/7 and follows me around like a lost puppy! And when I'm generally busy and can't hangout with him, he gets upset! He wants a relationship but it's going too fast for me! I don't want to lose him, that is NOT an option! But what should I do? I don't want a relationship yet😔 I don't know what to do!!!