literally keep forgetting 来月 every single time

so today i was trying to book a dog groomer for next month cuz my poodle is looking like a literal mop lol and i wanted to text my tutor about it but my brain just died. i always get 来月 mixed up with like 先月 and then i start thinking about 行く and the kanji just looks weird to me after staring at it?? why does this one word feel so impossible to lock down like is there a trick or am i just dumb