This has happened to me twice now. A few weeks ago I tried working out, but couldn't get my heart rate up and I just felt drained. During rests after warmup sets, my heart rate kept dropping to resting levels really quickly. So I just ended my workout before it began, and then I felt a bit light headed/spacey after.
Same thing happened today. Logging it to keep track, but it's odd. Hopefully I can solve it.
Going to start wearing my apple watch 24/7 again like I was several months ago to see what I can pickup from HRV and heart rate data.