What does 흥이네용 mean?

How do you say, "it'll be over before you know it" in Korean? I have a friend who's going off to do his military service soon. I wanna tell him that. I'm not sure if I should say the direct translation so I'm asking you guys for help. ^^

Please check if I'm wrong with my translation. 여기는외국인친구밖에없나요? <This/Here (account) is only for foreign friends?> 죄송합니다 못본걸로 해주세요.. I'm not sure about this one but it seems to be saying sorry.If my first translation is right, how do i say "Everyone is welcome (..similar to anyone can add me)" ?

Help me translate into Korean please. "give me your extra pounds." The situation is, I said I was losing a lot of weight because of stress and a Korean friend said that she's gaining a lot. I wanna comfort her by jokingly telling her to give me her extra pounds. However, I don't know how to write it in Korean. Help.

Any idea what this means? I posted something in Korean. Someone replied but I can't fully understand it. "저는한달에이키로씩찌고있으니까이대로라면."