You more or less just described exactly what ails me. I'm very reclusive and withdrawn, and I find all relationships difficult and awkward. Like you, I often lie and make excuses about why I can't come out and socialize. It is simply too draining and too scary to me. People are extremely confusing and I usually miss the point of conversations. This is mostly because I can't focus very well, and partly because people make me nervous and I'm afraid they'll insult me if I speak. Even if the discussion involves something I'm interested in. Oftentimes, when I DO speak, everything is jumbled and my words do not come out as I intended them. This makes humor very hard, but still, I often amuse myself with my thoughts and I do think I'm intuitive and funny. Just misunderstood and ailed.
My life is just one giant sequence of misinterpretations, strung together by embarrassment and anxiety. Obviously you're the same way. Like you, I avoid the people with whom I live. I sneak around so that they don't hear me, and hence I avoid painful and nerve-racking interactions. Also, I can't keep a consistent relationship and my romantic experience is pathetically shallow. I've had 2 girlfriends, one of whom I dated for 2 months, the other for 6 months. I did not have sex with either of them, and indeed I'm still a virgin. I'm 21 years old. This bothers me sometimes, but like you, I have bigger things to worry about. Confusion strangles my mind.
I'd say get help. Clearly you need it. I've had some therapy in the past, and it really did help me. Between counseling and medication, I saw some considerable emotional improvement before my second g/f broke my heart and I tried to kill myself. That was 14 months ago, and I've refused all treatment since. I guess I'm just apathetic.
By the way, I was diagnosed first with Major Depressive Disorder & Generalized Anxiety Disorder. After further counseling, they changed my diagnosis to Bipolar disorder. I was put on an anti-depressant, an anti-psychotic, ADHD-medication, and an anti-hypertensive. None of the meds worked like I hoped them to. I weaned myself off and decided to try and beat this monster naturally. It hasn't worked, so I'm probably gonna seek therapy again soon.
G'luck. I'd say you're Bipolar as well. But that's for the profs to decide.