You shouldn't feel self-loathing or guilt or any of that just because you're using drugs. Put the guilt and the shame to where it belongs.
You can and should feel bad about yourself if you've screwed over people who care for you, and that you're supposed to be caring about, in order to keep yourself supplied. If you've stolen from friends, or lied to your family or made people suffer or broken their trust for the sake of your habit. If you need to kick yourself up the arse, kick yourself up the arse for stuff like THAT. But there really is no reason you should feel awful just for the drug - taking in and of ITSELF.
It's not a bad or immoral thing to be using, it doesn't make you a bad person, it doesn't mean you're weak or morally flawed or deficient or some lower-class human, or whatever similar bullshit some people like to spew about drug users. From your own words in the original post, you're clearly liking it, it's clearly giving you something on some level you feel you can't do without. You need to ask yourself why that is. But in the meantime if you feel you have to have it don't beat yourself up over it, it's obviously fulfilling some function for you.
Keep in mind also that historically, before prohibition, any respectable person could walk into any pharmacy and legally acquire various opium preparations, and later morphine and heroin. Opiate use wasn't criminalised and it wasn't pathologised. And please don't fall into the black and white thinking trap of going, 'oh I broke my period of abstinence, I' ve fucked it all up now, might as well stop giving a toss and go right back to the races '. Too many people do that and it's self-defeating.
I just hope you're being very careful if you're anything like me. My tolerance drops very rapidly whenever I've reduced or cut out and it's a major risk factor.