To be honest, what you paid for it a few years ago is irrelevant to what it's worth now. Market conditions change and property is only ever worth what people will pay. Sometimes that's a massive increase and sometimes a big drop.
Often, people don't need to sell and can wait it out if the price they will gain will give them negative equity or mean moving up isn't really possible. Some people wait it out through a sense their property is 'worth more' than the market will pay. To be honest that's a bit daft, because it's only ever worth what peoole will pay at a given time.
It's often true that if yours has dropped,mothers have too and if you're moving up, it can actually make the jump to next stage easier. That's a key thing to consider.
Forget thinking if it in terms of what you paid 4 years ago. Think of it in terms of now and what you will realistically get and what you will realistically need to buy elsewhere and what you can borrow etc. These latter frigates are the ones that count for decision making.
If you want to sell you have to find a price you and buyers can agree. If that means you have to come down in order to sell, if you really want to sell, you just have to swallow it. But it is up to you. If you don't want to take the price the market will pay now, you can sit tight and just not sell. Depends what matters to you most.
Bear in mind prices might fall over next 2 years....it's pretty likely.