Im currently ‘seeing someone’ - we aint boyfriend and girlfriend yet.

Im in need in some people helping me out, basically we met 5 months ago and ever since we have been seeing each other. We have been planning christmas, birthdays etc as hes already got me presents however all of a sudden im getting a gut feeling that he isnt interested anymore... when im with him it feels okay but abit different but over text it feels off alltogether i ask him if hes okay just to check and he tells me that everythings okay. Am i just overthinking?? Or is it maybe just because the “honeymoon” period is over??