Was this a panic attack? Severe leg spasming

Hello, I had an awful experience last night. I have had panic attacks/anxiety for years but never ever felt even close to this and it has really shaken me up, I’m just looking for some reassurance.

I woke up at around 2am with a bit of stomach pain, decided to get up to go to the bathroom as I couldn’t get comfortable. I suddenly felt hot all over and a bit weird. As I sat up my heart started racing but I didn’t really think anything of it. Whilst on the toilet (urinating sorry) I think I started to feel faint, incredibly nauseous suddenly and hot. I felt like I needed to lay down immediately. I went back to my bed and just had this horrendous wave of nausea felt like I couldn’t get up or speak. Then started with the most bizarre shaking/muscle spasms I’ve ever had in my life. Both of my legs were shivering/spasming fairly violently like I was freezing cold and I had no control over it for a good 20mins maybe longer. It was really frightening I’ve never experienced this sort of muscle spasming/shivering before.

Weirdly throughout this my heart rate and breathing were fairly calm I just felt horrendous, I think this is why it didn’t feel like a panic attack to me, I just could not calm my legs down, I felt totally out of control and like I was waiting for something awful to happen. Eventually it settled down and then eventually stopped. But it is the most horrendous I’ve ever felt in my life. My legs were actually starting to ache with how much they were spasming.

I have been under a lot of stress lately and I know it could’ve all just bubbles over I’m just really shaken up (for want of a better term) and really need some reassurance.

thank you.