Didn't finish my longest long run today :(

Hello all, I am training for my first ever marathon! Today was my longest run, 18 miles, but I only made it to 12.6 miles. I am going to visit an orthopedic doctor this afternoon and plan to do some more PT.

Last week on my 16-mile run, I had a re-emergence of some hip labrum irritation which I went to PT for earlier this year. I've continued my exercises and completed a half with no pain after finishing PT. I strength train 2x per week. I pushed through the 16-miler, but by the end the pain was a 7 or 8 out of 10. It hurt pretty bad the rest of the day, but resolved by the next day. I set out on my 18 miles today, and by around mile 12 it was apparent my gait was being affected by the pain - at that point I knew to call it quits and see a doctor. I am suspicious of a hip labrum tear given some of my symptoms.

However, I am just struggling with it. I don't know how my mindset is so skewed to see a casual and completely successful 12-mile run as a failure. I also am gaslighting myself because the pain is no longer as bad as it was last week, but I also logically know that it's not as bad because I listened to my body and called it quits.

A lot of people on the MarathonTraining subreddit shi* on others for not running at least 18 or 20 miles in a training block, and I am doubting my ability even to finish at all. I also know that it is not advisable to try to make up the mileage - which is hard because I am supposed to begin tapering now.

Assuming all goes well at the doctor and I reintegrate in PT, will I even be able to finish with only 16 miles under my belt? Does anyone have any success stories finishing a marathon with less than 18 miles as their longest long run?