You can save this plant. First cut off all the flowers and the tips of the foliage. Hopefully you have put plenty of drainage material in the pot (like crocks in the base, and a grit mix in with the compost/soil). Next water it thoroughly, and let the water run away through the drainage holes. If you MUST leave it in the pot, raise it up onto three suitable blocks to enable drainage.
All plants need water, but some need to be able to drain really easily. In the ground this will look after itself as long as it has sunshine.
If this stays in the pot, you need to apply a heavy watering - but not until it has completely dried out from the last drink.
Cutting the tops off now will help the plant to bush out a bit and that will make a big difference.