Periods after c section

How long after a c section did ur periods got back to normal ? I had emergency c section in March and I lost my daughter next day . We want to try again but my dr advised to wait for 3-4 cycles . I ve only had one period after my c section and that was on 29th April . After that I had only spotting for 2,3 days when AF was due...I’m not pregnant because I never had unprotected sex.any suggestions or help ????