Sintari

So lately I have noticed my Temp gauge will rise when I turn my A/C on. A bud of mine suggested I have a blown HG but at idle, I have 1 or 2 bubbles come up in my radiator opening. So I dont think that is the case.

Now, a while back my car was really low on coolant, so I just filled it up with water and forgot all about it. Could that be my issue? It looks as if I am running 100% water in the thing.

Any advice would be helpful. Thanks in advance.