So I've been there myself. I had no idea what was happening to me, but it was the worst pain I've ever had. I finally called Al, who took me to the emergency room.
The first thing that they did was to take my vitals. I remember the look on the Doctors face as he took my blood pressure. All of a sudden the initial reason for me being there (I think they already suspected a kidney stone), everything switched to reducing my BP. I was quite literally in the stroke zone. Once they gave me some BP medication, and got that down a bit, then they switched back to the kidney stone. However, the kidney stone that caused that incredible pain was the size of a grain of salt. I actually thought at one point my appendix might have ruptured. I thought it was possible that I might die. That's when I decided to call Al.
The good thing that came out of that experience was that the ER Dr. made me an appointment to get more thoroughly checked out. That's when I discovered my hypertension. A week later my diabetes and elevated cholesterol. The meds that I take now are working fantastic at controlling those issues.
I just can't imagine a lentil sized stone! I thought I was dying from a salt grain sized stone. The stone passing through my penis was painless (insert large penis joke here). It's whatever vein or artery it initially traveled through that was excruciating.
I understand your pain and your panic!
I did not have any blood in my urine during my event, however 10 years earlier I woke up and went to pee and my urine was red. My Father had this happen several times. He also had hypertension. So I understood the gravity of blood in urine.
My panic completely left a few minutes later as I discovered the Red Velvet cake I had made the day before, and consumed some of had started bleeding the Red color through the cream cheese icing. Thankfully it was just the Red dye from the cake. That was the first and last time I ever made or ate Red velvet cake.
Just take this as a warning to be thoroughly checked out. If something is made aware from this, it can be treated. Don't be a dumbass like me and wait until your almost 60 to finally go to a Dr.
We're never bulletproof. Not at 60, not at 40 or even 20.