Clomid, thin lining... hopeless, help!

Samantha • Mom of a beautiful 2 year old, Emmy. Trying to conceive miracle #2, TTC for a year so far with PCOS.
So, took my first round of Clomid this month. Went in last Wednesday CD 14 for u/s... there was 1 follicle. I got a positive opk on Saturday, CD 18 and OB called today to tell me he wants to bump me up to 100mg of Clomid next month. Does this mean there is no hope of a BFP this month? If my lining was thin Wednesday, could it have thickened enough by Saturday? HELP!