This is a very brave expression of lonliness. You wrote it just the way it feels.
Lonliness could be in a crowded room...if you feel alone inside. I know just how you feel because this is my life too, except for some online friends. You can even be married but if two drift apart and feel unwelcomed, misunderstood, unloved.....the same feeling can set in. Every day becomes a lonely rainy day. What you said about friends is true also....you care very much but feel let down and the truth is you're really alone inside amost all the time. To keep from feeling totally heartbroken and invisible, the only thing I can say is to treat others with even more care, respect and kindness and some will come back to you. You will experience hurt when you try harder but you will also feel more moments of sharing and grace. Eventually, hopefully, you'll find one who wishes for nothing but to be by your side who loves you. Thank you for sharing your difficult feelings and know that you are not alone in them. Some days are so hard you wish you could just give up....but don't. Sometimes we learn our greatest lessons through our own personal struggle with lonliness and sadness.