Still getting used to my body not "cooperating"

bigbear

So DH and I went fly-fishing yesterday. We've been at this spot many times before and it is a rough terrain to get to the stream but I've done it so many times before with little to no effort. Well yesterday was a different story. First my legs were getting so tired, then I started having pains on my left side (felt like RLP) and then I felt faint! I had to sit down in mud just not to pass out. As soon as I'd get up everything would go black again. I had eaten plenty, i drank a bunch before leaving and was drinking water the whole time there but it was just too much for my body.

It is just so strange that things I was able to do just a few weeks ago are now simply out of the question... And I DO workout and walk every day so it's not like I"m just out of shape.

Anyone else having a harder time adjusting?