I feel that self loathing stems from early childhood experiences and also abuse, if you grew up with anyone who hurt you deeply and no resolution was ever given. It will definitely cause a sense of being unloved and without treatment you will not grow into a well adjusted person. I struggled with profound fear and insecurity along with PTSD, GAD and a low self esteem and lack of confidence. I struggles my whole life with these feelings and therapy didn’t work because I never knew how I got this bad, it took me my whole life to find out that I was seriously abused by an older sibling who hated me for being born and robbed me of my innocence, I started getting therapy for this and now I understand why I felt like I did. It’s not too late to find therapy for yourself because it can really help you put things into perspective for you, give it a try and see how you feel, it won’t hurt you and hopefully you’ll get rid of the feeling that you’re not worthy of being loved, best wishes to you.