Benzemek burada yalnızım. Its seems like I ma alone here . Thank you

In this case you should use the word "gibi" instead of "benze-" 

And "gibi" has to be the predicate of the sentence here...

So the personal ending must be added to it:

Burada yalnız gibiyim. 

"sanki" can be placed at the beginning (for more effect)

Sanki burada yalnız gibiyim.

Can we say :

"meğer burada yalnızmışım" ?

Anyone ?

you can say...when you suddenly realize that you are alone

 You can say so.

What about..

meğer yalnızım

no that´s not right because when you use "meğer" it means you did not know it before, so you have to use "mış" tense