Yesterday I sent 1.00/BTC.  

It remained unconfirmed last night.

This morning my wallet balance had increased by 1.00/BTC.

 It would appear the 1.00/BTC had been returned.

Nothing in my wallet mentions receiving it back, even though the balance increased.

I sent 1.00/BTC again thinking it would be sent.

When I checked on https://blockchain.info/  it has a warning about double spend.

Tx ID is 4276d4adede62170a5d0b7e7291f8a9ada4dd7267ee6ab739415e015d3db3daf

I have also sent another transaction this morning for 0.001/BTC, it has the same warning.

Tx ID   d3ca6ac5644bba0c7e91bf75b572663934e52d0c1d5a132a9dc33979ce3c61a8

I have no idea what is going on, I have never seen this before.

I don't want to use my Electrum wallet at the moment in case the above happens again.

Any assistance would be greatly appreciated.