I'm trying to conceive my 2nd baby and i've been having sex everyday and even when i got a positive on the prediction test but i'm still not pregnant?

How long trying?: Assuming you conceived "easily" before, there are many reasons why a second child could take longer. 40-50% of couples have sperm issues, and he could have a low sperm count even if same partner as your 1st child. You may have lower egg supply, ovulation problems or hormonal issues, or blocked tubes or scar tissue, sometimes after a c/section. Fibroids, polyps are common. See a rei md for testing.

Secondary infertilit: I treat many couples who had no difficulty conceiving the first time. Most are very frustrated that they can't get it to work out as quickly as it did the first time. Just a few years of increased age can slow things down. If you have been trying for more than 6 months i would recommend an evaluation - day 3 fsh, hsg and semen analysis. If all ok keep trying may just take longer due to age.