Pregnancy six months post partum

Patient: I am 6 months post patum and haven’t gotten my period back due to breastfeeding. i took a pregnancy test and it was positive but that was a month ago and i repeated the test at a free clinic and it was negative so i didn’t worry about it. i have been getting drunk very weasily and have heard from friends that it is a sign of pregnancy. i have also heard that when you start feeding the baby solids the chance of getting pregnant rises. is this a valid concern or as the test before probably invalid?