but I don’t really feel any guilt.
It depends on what you mean by “guilt.” Theologically, there is a difference between “guilt” and “shame.” Guilt–think of a court–simply means you accept responsibility for the sin. “Yes, I did it. I was responsible.” It does NOT necessarily mean that you are sorry or that you feel “shame”–“shame” in this sense being a deep feeling of sadness or worthlessness because you have sinned.
A lot (most?) people confuse the terms. “Guilt” has become synonymous with “shame,” and it’s not, at least in religious terms. “Shame” is not necessarily a good thing–if you feel so ashamed of something that you don’t seek forgiveness, or you believe that no one could possibly forgive you, that’s a bad thing. On the other hand, if you simply say “What was I thinking? Why did I do that? That was a crazy thing to do!” that’s a good thing.
But shame is not an essential part of sorrow for sin. So if you don’t feel ashamed (“guilt” in your terms), it doesn’t lessen your admission that x was a bad thing to do, and that you are responsible for doing it, and that you wish you had not done it (=sorrow for sins).
I find it hard to feel guilty for disobeying someone I cannot physically interact with in any way.
I assume by this you mean God, and not your mother who lives 1,000 miles away. Leave God out of it for a moment. In the Catholic church, morality is based on natural law. In other words, even if you were an atheist you should feel guilty for murdering someone or stealing or lying. Sin almost always hurts someone else. If you can’t connect with feeling sorry for hurting God, feel sorry for hurting other people–or even yourself. Getting drunk in your own home isn’t going to hurt other people (assuming you live alone), but it hurts you.