I’ve been taking the ‘Cerelle’ mini pill for about 7 months now and I haven’t had any trouble with it whatsoever but since 2 days ago I’ve been experiencing a light pain on my side, it feels a bit like cramping and today when I used the bathroom I had a bit of blood on the tissue and I feel lightheaded. I’ve never had this before, is it normal, could it just be a period?

Sounds like breakthrough bleeding, which is completely normal. The cramps are also a possible side effect. Side effects can still happen after the adjustment phase.