Hi Nafi, your profile says "London" so are you in the UK? or Canada?
In either case, the sun is fairly weak and the days are just getting longer. In winter, even house plants need less water and no food because it gets cooler at night indoors as well as out, and the days are shorter. If you didn't adjust your watering and fertilizing habits to compensate for slower growth the last few months, that may be the cause of your plants' problems now. They don't look like they are really dying yet to me, just somewhat stressed.
I'd advise you to put each plant laying down on some newspaper, and slip the root ball out of the pot to have a look at what's going on inside the pot. IF the bottom part of the soil is really soggy, fold up an old cotton towel or something else very absorbent, and set the plant on that to wick away some of the water. After doing this, just slip it back into the pot and don't water for a few days to let the air get in there to the roots that have been suffocated a bit by too much water. Then resume watering, but a bit less often until the days are longer and warmer.
If you find other problems when you look in the pots, take pictures and let us see.