Confused about Pressure.

In February, I hooked up with a guy who had been bugging me nonstop to meet up with him. Before meeting up, he had been asking me if I would be down for anal. I was very much against it and told him no up until the time we met up. In the middle of sex, he asked me if he could, I said no but he continued bugging me until I finally agreed so he'd stop asking.

After telling a couple of my close friends about this, they said that what happened was not rape, but was definitely not okay.

I don't know what to think. I didn't like it and would never do it again, but I did say it was okay so he'd stop asking.

Any advice is helpful.