Pregnant 1 month after SIDS

We lost our almost 12 week old baby girl to SIDS on 9/25. My husband & I both agreed that we wanted to have another but thought it would be best to wait 6 months until things died down. Physically, mentally, & emotionally I am still a mess from everything we've been through so I had hoped to get trauma treatment before getting pregnant again. I had been charting and keeping track of my cycle but because I had to suddenly stop breastfeeding and due to all the stress my cycle was off. My period was due almost 3 weeks ago but every other test I took up until tonight was negative. Now that I know I'm pregnant I'm panicking. I'm terrified of losing another piece of me.