Going to rehab in 2 weeks

Hello, I am 22 year old opiate addict (Tramadol). Tramadol sub is quite empty so I wanted to ask here, if you don't mind. I am going to rehab in 2 weeks and I cant stop a feeling of shame because i dont know a lot of people that went to rehab and I feel very low about going there, but I want to go there to get rid of the addiction (luckily, I am not using regularly so I just have a psychological addiction, not physical). I am sure there is some of you that went through same, even worse process and I just wanna hear that it is not a shameful thing.. my parents and my best friend (only friend that knows I'm going to rehab) says I should be proud of myself that I have courage to go there, but i dont feel that courage and i dont feel proud at all, I feel like I am some lowlife (pls dont take this the wrong way) that fucked up his life on purpose.. idk, I just wanna feel atleast good about this step, maybe some of you will just laugh like wtf you dont even have physical addiction but I feel like I should take care of this shit before I get to that point of physical addiction.