Have any of you pregnant ladies had any of these things that are listed but ended up pregnant?

I'm young in my 20s healthy been trying for 8 months and still nothing. The reason why I feel like I'll never get pregnant is because 
1. My weight. I'm 4'9 but it's super hard for me to put on weight my bmi is slightly low I eat 3 times a day but still can't put on the weight but weird thing is doctors aren't really concerned about it but I know you need a healthy bmi to get pregnant. 
2. I had chlamydia. Twice 😒 first time 2012 back in high school not sure how long to be honest but got it treated and the doctor wasn't really concerned about me not having kids. Second time for about 2 or 3 months got that treated also but I know it can cause infertility that's why I get so worried that I can't get pregnant because of that.
3. I have irregular periods. So I'm not sure when I exactly ovulate. I'm going to make an appointment with a ob gyn and figure out what's the problem hopefully it's nothing bad maybe a hormone imbalance but I'm not sure 😔
I haven't had my period for 2 months and till now I keep getting negative pregnancy tests trying so hard not to stress but it's getting very annoying I can't even count on how many times me and my partner have been having sex. I just have this gut feeling deep down that it's not going to happen I can feel it. I just wanna give up sometimes😔