Some answers to your questions:

In the end, everyone is forgettable and unimportant. I suggest reading Seneca's letters for more on this point.

Friendship is ultimately a fantasy, and as such you're friends aren't real (this is how it is for everyone).

In civilised society everyone pretends some of the time, even yourself.

Whether you're wasting your time or not depends on what you're trying to achieve.

The truth is always changing, there's no such thing as a final "the truth". We all have to move on anyway.

About worrying and paranoia: A paranoid person firmly belives that something, which is demonstrably not true, is actually true anyway. This is classified as a psychotic state. Worrying that something might be true, on the other hand, is perfectly normal, - although excessive worrying can stiil harm you. If you only worry about certain things, other things around you start to fall apart.

As a way to learn to deal with a worried mind, and seeing needless worry for what it is, I recommend Vipasanna meditation (Buddhist insight meditation):

http://www.insightmeditationcenter.org/books-articles/meditation-instruction/