Hay-eating is an excellent sign! Maybe he did have gas and you made it go away with the light massage? My bun Bam used to chatter his teeth when I did light belly rubs for gas – at the same time as he seemed to want me to go on with it. I never knew if it meant pain, self-soothing or that he was pleased (he frequently teeth chattered when pet as well), but the massages + gas drops worked many a time during his almost 7 years with me. I used to sit him in my lap with a fleece blanket on him to warm him up slightly with my body heat. Elevating the butt like Mary S Cotter suggests in this video: https://www.youtube.com/watch?v=JnuxGLa2reg worked well for us. If you’re lucky, you could even get to hear your bun fart =)
You can give baby gas drops, 0.5-1 ml, on suspicion of gas according to both Dana Krempels and MediRabbit. Simethicone (the active ingredient in gas drops) is not absorbed into the body, it stays in the GI canal and eventually gets pooped out. They rumbling in his tummy do signify gas.
If he starts pressing his belly even after having had gas drops (you can give 0.5-1 ml every hour for 3 hours, if it hasn’t worked by then it’s unlikely it will, but you can still give 0.5 ml every 2 hours for as long as you see fit), I’d contact a vet. You dont have to wait until he’s not eating and pooping, a significant decline in appetite + things like trying to hide, refusal to move from one spot or pressing the belly warrants a call to the vet. Depending on your description of his condition, they might want to take him in to give him fluids and painkillers and perhaps a motility drug depending on examination findings.
As I said in the beginning of my post, hay eating is a great sign.
You are allowed to ramble when your bun is poorly. It’s perfectly normal and I think all of us here can relate.