Any symptoms

So I have one child now before I found out I was pregnant with my daughter didn't have any symptoms! Only craved hot dogs! My hubby and I have been trying for 2 yrs to carry a pregnancy nov 2014 had a miscarriage, but I just knew I was pregnant right away I mean literally 4wks 1 day! Didn't take a test went to hospital was having pains! Now I have the same feeling this time around! I'm sleepy though craving hot dogs nauseous here & there but mostly tired! I know I'm suppose to wait til a day of AF OR day after but I'm impatient! Anyone sometimes just know? Or am I crazy?