Search Results: harder during sex

So I went out with this girl a few times, and things went well on our first few dates. She wasn't exactly the person I was looking for but I really liked her.
She seemed to really like me because she tried to be her best self around me and wouldn't smoke or do anything before or during our date because I didn't like the smell.
After a few months, we went out a third time and she was super excited to get together again, even asking to go to where we first met, then she explained she made a lot of bad choices during that month. She got into two bad relationships and got into drugs and had to go to the hospital. But she got a new job and moved back home. We had a good time, but she said she really wanted to focus on herself and get better, and didn't want to rush in a relationship, but was open to date and stuff until then.
We went to have sex, and she gave me a hard time because she had sex on the regular before we met, and I hadn't had it in 5 years. During which she just kept talking about her old partners and was just psyching me out and after a few minutes I couldn't maintain an errection and she seemed disappointed and I was extremely disappointed with myself. She spent the rest of the time in her phone, but told me as I drove her home I started good and she wasn't gonna hold it against me and we'd get together the next day and she gave me a kiss.
She rescheduled our plans a few times before saying she couldn't keep doing things with me, that she was gonna focus on getting sober and she's had a hard time with that and she hurts people when she's tried in the past. She said I'm a great guy and she wanted things to work. But she said she had a lot of issues to get through, and I tried to convince her I wanted to be there for her and after a little back and forth she blocked me.
I don't understand why? I said I wanted to be there for her