Some help please.

I started the pill a little less than two months ago. From the first to the fifth of this month I had a normal period. But then from the 25th to the 28th of this month I had an EXTREMLEY light one. Is that normal? And then I used tannins during the very light period(which I always use them) and I changed them properly. But yesterday it felt very itchy so I took it out cleaned myself and inserted a fresh one. I did not wear kne to bed last night as the period was over. This morning I woke up and it was sooo unbelievably itchy I couldn't go back to sleep. I for up cleaned myself and right now I'm fine. But I'm kinda scared. Any advice?