If you think you are alone just because you are single, you need to know that they are many queer couples who feel alone even though they are in romantic relationships. A person's relationship status never defines one's state of mind. There are many queer people especially homosexuals who are happily single and leading their singlehood as single gay fathers and single lesbian mothers. Do you know that you can date and still be single?
There's no wrong in being single and exploring the world out there in many possible ways. But there's wrong in carrying the aspect of loneliness everywhere you go. That's a flawed approach to life. If you wanted to be single, better stick to it and carry the relationship identity as you own it, instead of giving a chance to other people by suggesting you get a partner beside you.
Yes, if you feel alone, it gets surely visible on your face and people can easily sense it. We are humans and we can't stop intervening in others' lives. The people around you start poking you regarding your singlehood and if you start allowing their opinions and statements, you gradually get swallowed up in their darkness and you end up hating yourself, which is not at all good for your physical and mental health.