IS MY COMPUTER HACKED ?

Hello Everyone

i activated Safety feature on my facebook

So that if any one know my password, it can not enter

Because the security code up to my phone only

But from time to time I received messages on my phone telling me that some

one opened my Facebook account

How could this happen! Is my account was hacked? Or my computer hacked!

Or that the problem is on the Facebook site?

And for your information I activated too the safety feature to Hotmail and Gmail

but i don't received any messages telling me that someone opened

my account ..... and also i note the slow speed of the Internet from time to time