First time trying to conceive

I have used an IUD for the past four years. Before that, I used the pill. I have always had terrible menstrual cycles that would last a minimum of 6 days up to 10 days. When using the IUD I noticed after a while, I would have shorter periods and spotting only. What a blessing. Now that I'm trying to get pregnant, this first month without the IUD my body is right back into its old familiar ways. Am I alone with this pattern? Is this caused to uterine lining being excessively thick?