My prayers are on time, my heart is somewhere else

I still make wudu on the bus, set my alarm, and pray five times a day because that is what I have always done. But for months now my prayers feel like muscle memory. My lips move, the small kitchen at fajr smells of coffee and tea, and my grandmother’s du'as play in my head, but my heart is not in it. I feel guilty and confused. I am not angry at Allah, just numb, like I am going through the motions while my chest stays quiet. Has anyone else been here? What did you do, if anything, when the routine kept going but the feeling stopped?