The end of the honeymoon phase is upon us...

I've come to the realization that the honeymoon phase is over :( everything isn't rainbows and unicorns anymore. I've read lots of articles stating that this can actually be a good thing, because now a more comfortable, deeper connection sets in if you're with the right person. I can't help but feel like the end of the relationship is coming. I love my honey pie and I don't know how to interpret this time. My anxiety doesn't make it any easier because I start freaking out over the smallest things... I'm bummed out but I know this is inevitable! Any kind advice from those in long term and loving relationships?