TTC after baby

anyone try to conceive shortly after having baby? our daughter is 18 weeks now started trying at 5 weeks PP and nothing yet. I haven't really had a period just some spotting they Think is it coming back. but after so many losses I hate getting BFN but I've been testing every two weeks just to be safe. how do you deal with all the BFN it makes me feel like I suck at being a woman ugh thanks in advance