Trying for #4

Hello all. My hubby and I decided to have one last baby. We have 3 kids 14, 10, and 2. I just had nexplanon taken out of my arm in early May and have always had normal cycles while on the BC. I am just now getting out of my fertile window and we have been trying to conceive since AF ended. The two week thing is killing me and I am having cramping, headaches, upset stomach, I am peeing a lot more and can't get enough sleep. My lower back hurts more than usual. My questions are: could these be early symptoms or am I crazy for thinking we can get pregnant right away after having the BC rod taken out?  With all of my kids, I got BFP tests before AF was due. Tempted to test, but will try to wait!