Barely swimming, almost drowning

(Partially influenced by Stevie Smith's Not waving, but drowning).
 
It feels weird to say this, but I came back on holiday recently. I've not felt so good in such a long time - but it seems that all the energy I seem to have is being used to maintain and display my new positivity. I suppose a whole new mindset would be a whole new playset. So instead of being tired, lethargic and disinterested, I was hoping the new view would mean a whole new act - but it's taking all my energy to appear positive, interested and mildly energetic - the truth seems to be that while I am slightly more positive, I have all the energy of a dead kipper. Smiling seems to take so much effort, I thought once I'd find a way past the moodiness, it would be a whole new ball game, but it's the same ballgame, just dressed up. I thought I'd find a way to break the cycle, but I think I've just found a new way to fool people - me included. Was my new outlook just a mask, a lie - was I lying to myself... I don't know but I really had hoped that this would be the first step towards a brand new, re-invigorated me. But instead I have the energy to smile, to do one thing, and then I'm back to lying down all week. The only difference is that now I lie with half a smile plastered to my face...
what's going on... just don't know what to think. I'm more positive, i have a greater self belief, but I feel like I have half the energy I did before - which was hardly any, now hardly any seems like a whole lot more than now.
 
what's going on?