Need advice. Trying to conceive

My LMP was on January 20, We had unprotected sex on Jan 28, Jan 30 and Feb 2. I have a 26 days cycle but sometimes it's early 1 day and I never missed my period. And my period last up to 4 days on regular months. so I supposed to have my period on February 15. But 3 days after my expected period, It was February 18. I had pinkish blood, It's watery. And it's not normal because I always got heavy bleeding on my first period. The next day, Feb 19, my period was stopped. Feb 20 morning I went to OB said I'm not pregnant and it's not implantation, And it's normal. But the afternoon same day, I got my lightly period again but it was stopped on night, It was dry red brown on my pad. Feb 21, Feb 27, I took pregnancy test and it came out negative. Also on March 5 It was also negative. But I already had a milk on my breast when I always press it. Can I have a baby even I always got negative results on pregnancy test💔I tried different brand but same result. What can you advice on me? I hope you all guys can advice me and enlighten me. Please respect my post. #advicepls #pregnancy #pleasehelp #pleasehelp #pleasehelp