I have felt like giving up over the 20 odd years I have had depression. Many times I have said I cannot go on, it is too hard. But I am still here and battling this illness that has taken over my life. Many people here will say the same. Life is too much of a struggle. I am worthless.
Would you like to elaborate on why you say you are living a lie. Is it that you pretend to others that there is nothing wrong with you? You can "talk" to us, we do not judge. Open up, and perhaps you will feel relief that you can tell people who understand how you are feeling.
Believe me life does lose its meaning, and we wonder why we go on. Most of us do though.
Your life is not meaningless, nor is any one else's. If you think you're life means nothing why not come clean to the people you love about the lies that your 'telling?' I'm no doctor or anything so I believe if it's personal. Why not see a councilor about it?
Just remember your life is not meaningless :)