I agree with Chuffy she has given you good advice, if you drop your syns you will have nothing to fall back on if you reach a plateau in your weight loss, when this happens if you you are eating your syns you will be able to drop them and kick start your metabalism again.
I'm sorry that you have gained, but just forget that now and start again, do what Chufy has advised for this week and you should lose again next week, good luck to you.