Post-exercise fatigue

[Monstercarp]

Hi,
Just started going to the gym, have done some yoga, swimming and gym sessions with a PT with no real issues.
I've done a couple of more intense classes for cardio but find that afterwards I feel ridiculously tired all day. I'm constantly yawning, feeling hungry (despite eating both before and after), and feel real achy all over.
Just wondering if it's normal to feel like this when you first start working out?

I'd say you are probably dehydrated. Make sure you drink before and after (I'll have at least a litre after a run, more if it's a long one). It's crazy how much you lose in sweat without realising.