Hi thanks for your question.
No,these are not symptoms of pregnancy
.Your on bith control pill and has not missed your period,so chance of prgnancy.Changing of brand of birth control pill will not affect your contraception
.Abdominal cramps and bloating
could be due some other cause.May be due intestinal infection or acid peptic disease
.slight vaginal bleeding could be due to local cause in vaginal,not necessarily from uterus.I would suggest you to consult a gynaecologist who may be able to evaluate you for your symptom and may prescribe you appropriate treatment.
Hope this answers your question.