Pregnant Right After Birth - Irish Twins - Arm Implant Fail

L
So... I had my son 8 weeks ago. Until my 6 week appointment with my OB, my husband and I had sex twice and used condoms. I DID NOT want to be pregnant again for a couple of years, for obvious reasons having just had a baby. At my OB appointment at 6 weeks I had the arm implant put in, and had to take a pregnancy test in the office to ensure I wasn't pregnant prior to the implant. It was negative. My OB put in the implant and told me it would be effective immediately, and since I'm also exclusively breast feeding, I didn't need to use a backup birth control method. I waited 6 days from when I got the implant before we had sex. Fast forward to now- I'm 8 weeks post partum and started feeling pregnant yesterday (super tired, crampy, etc). I took a test on a whim - and a faint line appeared. 😱 I went in to my OB office for bloodwork and will get a confirmation Monday, but based on the faint lines I'm getting and the way I feel I know I am pregnant again. I guess I'm just looking for some support. We weren't ready for another baby, and I wanted to keep breastfeeding. Any words of advice / similar stories? I'm feeling guilt for my current son. How will I be a good mom when I'm sick and pregnant. Will I even be able to lift him?  I don't think I'll be able to work at all with 2 babies under 1 year old... How will I do this!? Thanks ladies.