I see my future being single.

I'll give you a thought that I'll probably be absolutely looked down upon for

I used to follow the 'be yourself' advice, and I was absolutely depressed and had a bad time trying to get anywhere, not just with girls

Then I had a thought that maybe I shouldn't 'be myself', as it seems too general of an advice. Instead, I tailor my interactions with different people in different ways, and I've had absolutely no problem since. Now, to be myself is to always be changing.
Think of it as a job application - you have a general CV but if you want to succeed, then you'll tailor your CV and form a cover letter to suit the job more specifically.

Don't follow cliche advices just for the sake of following a general guideline - you've got to 'be yourself' and not conform to general social templates

Also, dont base your life around meeting girls

However, I can't help but think of this.

If your life is based around meeting girls, then you're bound to have a bad time. Your life sorts itself out if your work is going well
Snap out of it, focus on your work, and you'll see that you'll have more opportunities to meet girls. Speaking from experience here.
Why would girls want to date an obsessive guy who only focuses on girls? Surely confidence and success is a massive factor in your attractiveness to people, right?

However, I can only show you the door and you'll have to walk through it !

So, one of the most cliché advices I've ever been given is to 'Be myself'.
So to be forward with that idea, I have been for the past 20 years and in that time I've blown countless opportunities to express myself with girls.
So in hindsight I'm depressed as I can't see myself moving forward.

Here's something to think about that might cheer you up.

Despite all the fairy tales and what you watch and read most relationships suck big time, and Shakespeare won't get out of bed to waste ink on them. Over 50% of marriages break up. As for those that don't, most couples stay together out of inertia or the financial consequences of splitting up. I'm single and laughing my head off at all those who got conned into marriage (or some kind partnership). Yes if someone with the looks of Helen and the virtue of Penelope crossed my path I'd be up for it, but I now know that such relationships are well and truly one in a million.

Roses are red.
Violets are blue.
I'm single and happy,
and laughing at you.