Give Me Some Hope - Thin Lining Cycle Day 8 for Mod Nat FET Cycle

Little background I’ve had two modified natural cycles canceled due to my progesterone being over 1 before being able to trigger. Just had a failed fully medicated cycle last month. Dr suggested we try modify natural again. Took 2.5mg of letrozole cycle days 3-7, I went in today - cycle day 8 and I have a 15mm follicle but my lining was only 4.2. Still waiting on my bloodwork but any success stories with lining being so thin on cycle day 8 with a 15mm follicle?