How do i fix it. I dont remember what my pin was from last year

If you're talking about the 5-digit efiling PIN, it doesn't matter what you used last year.  You can select a new one -- just select any 5 numbers.

It didnt give me an option to reset my pin. Where csn i find that

Just enter the PIN during the filing interview--it's not a matter of resetting it.  
As you go through the filing interview, you should see the screen, "It's time to sign and transmit your 2018 return."  There is a box, "Enter a 5 digit signature ID."  Just enter any 5 numbers you want.