Trying to conceive. Issues or infection?

I had one spontaneous miscarriage 7 months back. It was on 5th week and happened automatically. Pregnancy was confirmed by scan and hcg test. After 2 months, I tried to plan again for 5 cycles. But did not conceive. Currently I am on 6th cycle (2nd cycle of OI). This is I am planning for second child. My first child pregnancy and the miscarriage was happened naturally. What could be the reason of delay in conception? Or it is normal that sometime it takes to get pregnant? I will go for HSG test anyways after 3 ovulation induction. But as per your experience can tube get block automatically suddenly without and issues or infection? My gynaecologist said leave the thinking on getting pregnant and stay relax. It will happen. The more we think, it will take more time. Kindly advice I am very much worried for this. Before some months I got pregnant naturally without planning. Even in pull out, I got pregnant. What happened suddenly now it is taking time, don't know.