Arm birth control

I became pregnant the first time by lack of contraceptive and naievity at age 15 by a verbally and mentally abusive guy. 7 years after my first, I'm in love with someone I couldn't be with when we first met but just adored (he was 15 and I was about to be 18, had a kid, so I tried hard to keep my distance) we became pregnant in March 2014 by using condoms and plan B. I used Plan B 3 times and it didn't work. We were meant to have our beautiful son who we adore. We decided we wanted to get married and wait 3 years before planning another baby so I was put on the BC pill once I stopped nursing at 6 months. I took it everyday at 9am religiously for 6 months and I had a gut feeling something wasn't right. It wasn't abnormal for me to be a day or two late but I looked at my calendar and I was a week late. I took a pregnancy test and sure enough I was pregnant again. I cried and cried. We were in complete shock but that quickly turned into excitement. We love all of our little ones but are adamant about waiting 3 maybe even 5 years before having another one. I don't want to do the uterine implant Bc I don't feel comfortable with the idea but am VERY interested in the arm implant. Has anyone had any scares while on it? How easy was it to become pregnant after its removal? Would you recommend it?