Is it normal for things to seem "different" as a relationship goes on?

Been dating my gf now for a few months so the novelty is starting to wear off, I still love her and spending time with her but things seem a little different and I'm not sure why.

The goodmorning texts are rare now compared to everyday even with goodnight texts even though I try to send them everyday just out of habit. She seems the same in person however she's still excited to see me and is lovey and all that and cuddles me but things just seem less interesting is this normal?

It's causing me to overthink and wonder if something is wrong in the relationship but then again nothing on the surface seems wrong at all.