**TW** Stillbirth at 23 weeks and becoming pregnant after?

So I just turned 40 on the 15th of April and on April 1st at my OB appt, I was told my son had no heartbeat at almost 23 weeks. We weren't actively trying when we got pregnant at the time. We have 4 girls and 1 boy altogether (2 girls that are ours together) and we were ecstatic when we found out we were having a son. Anyway the stillbirth of our son was devastating and i delivered him via c-section that day. Fast forward 2 weeks later, my husband and I have been very close and in love more than ever. We have been gravitating to eachother more especially because we are both grieving and we both provide comfort to one another. Well we ended up making love and have continued to do so ever since. We've had like 2 separate intense times where he didn't pull out. Has anybody been in a similar situation of having sex and becoming pregnant right away after a stillbirth or birth of a child? I took a cheapie pregnancy test today and it has a faint line but I read that hcg can stay in your system for a few weeks.