Why are my stools never soft!

I take 500mg sometimes 1000mg of magnesium, fibre supplements, 3-4 litres of water a day. Nothing!

This just recently started over the Christmas break. I've been using this suppository in order to make sure I don't re tear (all of these stools would have retorn).

Help! Does anyone know what to do?

Edit: thanks guys! I stopped the fibre pills and stuck to just magnesium pills, and I'm all back to normal :)