What am I doing wrong 😔

Carla • Happily married💍 mother of four, baby #4born on April 29-2022💗🎀

My AF came today and honestly Idk what I’am doing wrong... it was so easy to get pregnant before and now feels sooo hard ... I try not te get frustrated but I can’t help it ... I don’t get it ... am I not ovulating? Should I check my husband’s sperm count? ... Am I being silly for feeling like this after only 4 months trying?... 😞