Things like consumables aren't that effected by seasonal sales usually, they are things people need no matter what the season. You have to bare in mind that many have given their credit card a good bashing over the holiday season, so if it's a product they don't really need, many will hold off until the money situation starts improving again.
So it does heavily depend on the products themselves.
The best thing you can do is just monitor the situation and chart sales flow over the next 4 weeks or so. I would expect normal trading numbers to be returning by mid Feb, so if they aren't, then you need to look at the changes you've made.
Have you thought about setting up a second account and selling against yourself?
Sounds bizarre, but it can be a great way to market research. You set up another account selling some of your best selling items from your other account, but change up things like shipping and so on, then over one or 2 months, take a look at the sales date from both and you get a good idea which is working best.
That then allows you to hone a single platform or if both are working well, then don't fix what isn't broken!