I miss my iPhone but already have a new one?

So I bought the HTC one with a mobile plan contract. But I have a problem now because I really miss my old iPhone 4 really bad but my mother is using this one now. What should I do? I can't sell the phone 'cause that would be a waste of money I have spent on getting it (99 euro). Should I tell my mother and aks the phone back or should I move on and wait for my contract to end (2 years)?

You could talk to your mom and ask if she wants to switch.

Once you start using iphone it becomes difficult to shift.
but believe me HTC one is much better phone when compared to iphone 4.
but if you really want your phone back you can ask your mom to return the phone and give your HTC to her.

But it would be waste of money. You can wait for your contract to end and buy the latest version of Iphone then.

Offer to swap your phone with your mums?

I would forget about the iPhone now that apple has turned it into another one of the androids. No point in getting it back if you already have an android.