I've been seeing this girl for a few months now, we're friends and she hinted at wanting to have sex, so I set up a meeting, escalated etc. When it got close to penetration, I lost my erection. (She's my first)

I get normal morning wood, random boners and can usually get it hard on demand, but nothing with her worked, so we just called it for the night.

The second time we met we tried getting comfortable, gave her a good massage, fingered her a bit and lots of foreplay. My dick didn't care, so she finished herself and went to sleep.

Since she's way more experienced than me and I'm a virgin, I guess I have performance anxiety. I went to my doctor and got a Sildenafil prescription. I told her about it and we set up a new meeting.

I took 50mg of Sildenafil, and after about an hour we started getting comfortable, Massage, fingering, and during fingering her my erection was there, pretty hard too (also had some boners before). After getting her off through fingering I put on a condom but the erection faded. She jerked me, I tried as well but it wasn't getting hard. I let some time pass and masturbated a little and got it hard again, she came over and it went flaccid almost immediately.

The first time we met I hadn't watched porn or masturbated in 3 weeks, I figured I would start masturbating again for the second meeting and while my libido increased it didn't help.

I'm mediating daily, taking vitamins and I'm doing HIIT every other day. I sleep well and I'm hydrated.

What can I do? I'm afraid to lose her if it doesn't work next time.