Beginning to explore sexual and relationship issues

Hi everyone,
I've recently started to look at my sexual/relationship issues and my fear of abandonment.
I have two examples of what I think was disassociation or severe anxiety triggered by fears of rejection or abandonment.
The first occurred with a former girlfriend about 5 years ago. It was one of my first sexual experiences. I couldn't get aroused and I started to get anxious. She made a comment that "maybe we didn't have sexual chemistry". I think that was a trigger. I remember feeling really anxious and then feeling like I was struck by lightning. All I could do was lay in the bed all night, and it felt like I was continuously having panic attacks. I was having numbness all over my body. All night she kept asking me what was wrong and I just kept saying it was nothing.
I was depressed and anxious for several days afterward. Throughout the whole thing I had this massive fear that she would embarass me in front of all my friends because of it. I felt deeply ashamed.

The second incident happened about two weeks ago.
I asked a woman if she wanted to hang out, she said that she did.
I text her and we make plans. She doesn't text me back and I start to get anxious.
I took some advice from someone who told me to sort of lay out exactly what you wanted out of the relationship. I'm kindof harsh about it,I said I wanted to date her, and she told me that she was actually still in a relationship that I wasn't aware of. She's upset by my asking her, which I did in a very harsh way.
She tells me that we should just be friends, I say okay.
Over the next day I start to get severely depressed, I cannot get the situation out of my head. Eventually I collapse out of exhaustion. I felt like I was sinking into a hole. I spoke to my mom, she gets upset because she has never heard me so depressed. Strong sense of shame again, and also the feeling that she is going to tell people or embarass me. Now that I'm writing this I can't even figure out how that would happen, she doesn't really know anyone that I do...

This incident led me to learning about BPD. I am still undiagnosed, but this is the mental illness that I think I have the most in common with.

Both incidents happened during times of large stress in my life.
I've never really told anyone about the first incident. How do I start the healing process from these events? Has anyone gone through something similar.