Fish oil - I'm worried

Before i was pregnant and so far this pregnancy i have been taking a high dose EPA Fish Oil Concentrate 1000mg tablet daily which consists of 1000mg fish oil, EPA 180mg and DHA 120mg. Somebody has told me that it is dangerous to take fish oil. I know it is dangerous to eat too much oily fish because of the murcury and that cod liver oil is dangerous because of vitamin a. Does this apply to the tablets i've mentioned? Can anyone please advise me as I'm really worried now.