you have experienced loss of loved ones and are experiencing pain and lonelyness... and that is good! for you are a human being with feelings, don't ever think that there is anything wrong with that! for what would we be without our feelings...
i hate to use such cliche-sentences but: time will make you get over it. but only, if you don't give in to your sorrow and still have hope left.
u should try to spend time with other people and really try to get distracted from your problems (you can't have fun when you are always thinking about that), you may even have to force yourself to have fun
and with the time you'll discover another person who is worthy of deepening your friendship with him (but really take your time, for disappointments are crucial in your condition... and good friends are unfortunatley rare)

"I feel like real friends don't exist"
of course they do, they are hard to find but it's totally woth it once you found one.
when random people over the internet can show you that compassion, then surely there is a flesh-and-blood being near you, you may call a "real" friend after some time

i hope this helps you a bit