I wish you would let me know and I wouldn´t need to worry so much.

teğet ´tangent´

My guess:

For some reason years have passed and hardly left any mark on you.

(I am not sure if one can say in English ´Years have treated you well.´ )

My Try:

Others  -  when they go away they are gone,

but you  -  even when far away, you are still close.

The actual reason is historical: they are (Arabic) loanwords. There is no problem in placing l and ı in a row, it happens all the time.

My Try:

I felt in my bones that you will leave.

Loneliness greeted me.

Why don´t you look into my eyes, say it to my face?

I thought it is real but to my surprise it is just a dream.

The oppressor is a loser even if he is considered victorious, the righteous person is victorious even if he is considered a loser.

(Not word-to-word, tried to make it flow smooth. But this is the thought.)

I have a sweetheart. She has a very pretty nose. I have a sweetheart. She has a face like the sun. I have a sweetheart. She has hands like cotton. I have a sweetheart. She has a laughter like gold.

(After a shocking situation: )

Aklına sahip çık!

They are minor differences and it is best to ask a native expert to explain them. tunci? scalpel?

With singular, I think the attention is more in the action than the object. Like...

                      Çiçek aldım. > ´I made some shopping  -  flowers.´

Plural is more complicated. Certainly it is the marked category here, i.e. adding LAR adds something to the most obvious meaning:

                      Çiçekler aldım sana seversin diye.

Definiteness it is not. At least not grammatical definiteness. What is added there then? Abundance, feeling, attention to the object? Only enlightened natives can tell. 

Why lastik aldım if it is more than one?