First time using clomid

Hey guys,it's my first time using clomid this cycle. 
Iv been ttc for 19months but have Pcos so my periods vary anything from 30 day cycle to 94 day cycle being the longest. 
I took my first tablet yesterday (25mg,half of 50mg tablet).
I'm taking it on day 2-6 of my cycle.
Just wondering a few things. 
1.how bad are the side effects and when will i start to feel them? 
2.when is the best time to have unprotected sex? 
Thanks for any info xxx