So much mental energy required and why?

Why is it that when talking to an NT or a group of NT's that mental energy levels almost become depleted? Why also is this worse when contemplating relationships?

It just seems that socialising requires so much mental energy and one feels exhausted within and even more so after the process. Often just being within your own company provides a safe haven but there are times that you also want to be around other people.

I often find when sitting with a crowd of NT's (People not on the Autism Spectrum) that I find I am always on the outer. I just feel like I am observing the socialising process but not a part of it. No matter how hard I try to follow the conversation, I just find myself unable to keep up and maintain the mental energy required in order to be part of the conversation. I find sensory issues become a problem and I start to feel awkward and wonder how I can prepare for a plan of escape.

I get nowhere with relationships or dating and I have virtually almost given up. I am starting to become used to my own company. I don't have any hassles, I can function better but I often find anxiety a real problem. I feel largely self concicious in certain situations and I feel unsafe in loud, noisy or night club environments. I just don't feel I can trust the people and the sensory sounds just drive me into sensory overload or panic. Also my ears start to hurt and my eyes feel like they are being hit by 1000 lightning flashes. All of these just makes me think, solitude is so much better. Nobody can interfere with my space and I don't have to cope the sensory issues and more importantly where uncomfortable clothes that really irritate my functioning.

As an Aspie I constantly look for errors or faults in everything around me. It is like my mindset is driven for perfection. I see flaws in people and people who claim to be friends. I have to use more mental energy to safeguard me from my residual naivety and this makes me increasingly weary of people. For some reason I tend to trust Aspies more and find the social pressures less. It is like we are a community of immigrants on planet earth and yet we remain on the outer with people around us. We look like them but our mindsets think differently.

I need time out from vast energy consumption and when I have to interact I look for buffer zones and ways of recharging my batteries so I can again function where I need to. I also when totally drained mental energy wise tend to slur words and find some levels of function requiring some extra storage of energy just to help get me through. My mindset becomes more literal and I start to psycho analyse even more. Also my body just feels like shutting down and this is the time to be careful of so as to not avoid burn out or meltdown.

People cannot always see what is happening internally but trying to ride the rollercoaster is something to always be aware of and to adjust the brakes where necessary. I ask you why is so much mental energy required?!!