Scared to post this but..

So on Monday I went to the doctor cause I needed to refill my birth control. I asked that he checked me for stds and pregnancy cause I've just needed to ease my mind lately. I had sex with a guy in October, I've been friends with him for a year, but we weren't close or anything, we just talked occasionally, well I ended up having a one night stand with him. He was the 3rd person I'd had sex with, but I have been tested after the first two and I was clean, and I got tested with him, wensday morning, the doctor called with my results, I have chlamidiya, which for all of you who don't know, it is the most curable std, you take antibiotics two times a day for 10 days, sometimes you might have to do this a few times, but you can get rid of it. I told him of course, and told him to get tested before someone else gets it. I was so angry, but I knew it was my lesson be learned from having unprotected sex 3 times.I put myself at risk. But you see I've been dating my boyfriend for almost a month, we don't plan on having sex yet, but I don't know if I should tell him or not? My mom said I should just not say anything, because it'll go away, and I won't have to worry about it ever again. I just don't want him to look at me differently and think I'm dirty, he knows of my deeds but he accepts those because he's done his deeds as well. But I just don't know I should tell him or not, I tell him everything, he's like my best friend.. Advice?