TTC baby #2

Hello,

Just getting feelings out here. I’m frustrated and very sensitive to this situation. We had baby #1 august of 2020 and I got pregnant right away off the pill. I went back on birth control after I was done pumping. We are now trying for baby #2. We have been trying for a 4 months with no luck. My cycle is all out of wack with periods being 35 days between to 24 days between. Is this normal that I conceived right away but now I am not having any luck? Should I be worried?