4 months postpartum and pregnant!!!!

So.... I took a test and it’s positive. So many thoughts are running through my mind right now. How could’ve we have been so irresponsible? Is this unfair to my 4 month old? It’ll be cute for them to be so close in age though. What will my family say? I didn’t think I would get pregnant so fast. I struggled with my first. My DH and I tried for 3 years and with this pregnancy one slip up and Bam!!! Im sure everything will be ok. I hope everything will be ok