I vote purpose. Somehow, some way all that we go through is preparation for something that is coming up ahead.
Life is long. You can fall in love at any time. The only people who can go through life alone even if they want to have to consciously decide to and make efforts to do so. Try not isolating yourself and be around people. That should work.
If life has no purpose then no one is "meant to" do anything. Being sad or happy is up to you.