clomid cycle day 30

Michelle
Hey guys.
 I'm on cycle day 30 and at my 21 day progesterone check my doctor said I DID ovulate. 
I've got constipation/indegestion and very sore nipples. 
When should I take an at home pregnancy test
My cycles are normally 35-38 days so I don't want to take one too soon and get a negative, but I thought clomid made you start your period earlier? 
Any advice? 
Thanks!