i take 0.5 mg of klonopin a day that was never prescribed to me.
Then you are breaking the law. Penalties would be the same as for an illicit drug, both for you and your supplier.
i am afraid of celexa because i read that it can cause suicidal thoughts
This is mostly a beat up, not helped by the FDA issuing a blackbox warning for those aged under 25yo a few years ago despite the evidence not supporting it. One consequence has been that some doctors stopped prescribing antidepressants to those under 25 which saw the number of attempted and completed suicides among that age group rise after decades of steady decline. There is also an initial spike in suicidal ideation in those treated by psychotherapy.
and mania and heighten anxiety.
Mania affects a small number of those prescribed SSRIs, I'm one of them. Increased anxiety in the first few weeks is very common, which is why those with anxiety should start at low doses. For Celexa, no more than 10mg, and some may need to reduce it to 5mg for a week or two. Ask your psychiatrist for permission to cut the tablets in half for the first 7-10 days - DON'T
do so without getting the okay first as, although unlikely, there may be reasons why this is inappropriate for you.
i have a lot of irrational thoughts/fears and i am afraid that i will be one of the people to have these side effects. and psychiatrists will probably be mad because i'm not taking it.
If you expect to experience these side-effects then you proibably will. The mind is very 'good' at playing tricks like this. However, while starting antidepressants isn't always a barrel of laughs, most people manage it with minimal drama. There is no reason why you shouldn't.