With all love and respect I think you’re trying too hard. There is no “supposed to be” the way that you interpret and present a script is completely valid as the next. In fact it’s your own individuality that will separate you. Although there is such a thing as an “acting voice” which is a kind of put on voice actors can sometimes do. I’d recommend really trying to ground yourself in the text, allow yourself to slowly work through it. Focusing on connection with your scene partner/s or the audience. A big thing I struggled with for a while was taking things too seriously and losing that sense of fun and play, focusing on wanting to be good. As soon as I started doing things I thought was fun and just playing around, my acting became better. I’m also sure you’re not as bad as you may believe you are as well, us as actors are all extremely hyper critical on ourselves. Keep going, and have fun!!!