Birth control

I was on the pill for 8 months, had a break and decided to go back on it. I'm quite far into my second pack and missed one pill which resulted into strong pains so I had a feeling my period was going to start, I went to the toliet to find a minimal amount of blood but it just looked like old blood but I put a pad on anyway and all I have in the pad is a tiny bit of blood, the period pains are still coming along with sore boobs. Is my body just readjusting to the pill? Thanks in advance