I don't mean to worry you by saying this, but it is something I relate too a lot. I was bullied through school, suffer with abandonment and trust issues and I have borderline personality disorder. Severe fear of abandonment is a big symptom. It can be really hard to deal with worrying about being abandoned but you have to rationalise your thoughts and feelings.I have severe self hatred issues and have battled with low self esteem nearly all my life, I think it stems from my childhood and being bullied for most of it. It’s now so bad that from time to time I get anxious/panicked over the tiniest things like my body image, my boyfriend not replying to me or wanting time alone. My trust issues and abandonment issues are ginormous and it’s really hard to let go of them. I keep overthinking lately about imagining scenarios where my boyfriend is cheating on me. I feel so sensitive like a house made out of glass I feel like I could shatter at any moment. I feel so scared most the time and idk over what. I guess the fear of being left behind, of being abandoned. The crazy thing is I have no reason to even feel this way!! My boyfriend always shows me he loves me. But still I get these thoughts in my mind and I wish I knew how to let go of them.
I recommend seeking some support with this! It's impacting your life so much, (of course not saying you have BPD) but since I can relate to these feelings, getting some therapy and speaking to someone about how to deal with these issues are important. You shouldn't have to live in constant worry and suffer from low self esteem.