Chance of being pregnant

Hey all. My husband and I had sex when I was 8 weeks post partum. Apparently it was really good because my husband totally gapped and didn’t pull out… condoms are now very much a part of our future lol. Anyways, I thought I had a period at 6 weeks post partum but now haven’t gotten one again. I took a pregnancy test one week after “the incident” but it was negative. I am breastfeeding so I know my period will be all over the place but I’m wondering when I should text let again ? If it’s still negative should I assume not pregnant? Thanks in advance! We aren’t upset as this was our mistake but the waiting game is tough lol.