Text MSG problem

I have an iPhone 4s - I've had it for 3 months now and no problems up until now and it's a rather odd one that I don't know how to explain really so ill do my best.

When I have a conversation with someone through text messages or iMessage, either one, what seems to suddenly be happening now is their reply I don't see until I go out of the conversation to the messages area.

For example:
I'm texting my mum.... So my usually screen will show "messages" MUM "edit"
Then the conversation..... BUT NOW... When she replies to me I see...
Messages (1) MUM edit
And I have to click on that to go back out to the list then click on my mums name to see what she just wrote.

The next weird thing is that I can see the elipsis (...) when she's typing but then the message won't pop up as it normally would.

Anyone know whats going on or how to fix this? I have the latest update.

Thanks!

 

I was going to reset my phone this morning but decided to try and just shut the phone off completely. That seemed to fix it for now.

If it keeps happening I'm bringing it back to the reseller.