Unusual symptoms

I went on the pill in jan after 3 years ttc and a miscarriage. I had heavy bleeding for the first 3 weeks on the pill so had to stop it. Since then I haven't had a period apart from 3 weeks ago I had a very light brown discharge on and off for about a week and twice I had a very pinhead size red blop in it. Since then the last couple of days I've had very sore nipples/tender breasts (don't normally get it) I'm also feeling sick and tired. Is there any chance I could be pregnant or is it just my normal period starting ?? All thoughts are appreciated.  X x