It is time to find another psychiatrist. The combination of drugs you are taking is dangerous. Before I say anything else I warn you to not suddenly stop taking anything you are taking now. Note: I am not a doctor.
First, you should not be taking Celexa. That is Citalopram and was some time ago replaced by a much purer form that results in the dose required to be reduced by three to four times with the same effect. This is much safer. The drug is ESCitalopram with one brand name Cipralex. I take it and use only a 5 mg dose and it works well.
The Prozac, Celexa and Seroquel all have the effect of increasing your QT interval in your heart. Taking even one of these is a good reason to have an ECG done to verify your QT interval is still in a safe range. Taking three drugs that increase QT interval is just plain dangerous and could easily increase the heart QT interval enough to cause sudden death due to an electrical heart attack. There is no good reason to be taking these three drugs at the same time.
Here are warnings from Medscape, a website that is part of WebMD and works directly with the FDA.
Prozac (fluoxetine)
Serious - Use Alternative
citalopram and fluoxetine both increase serotonin levels. Possible serious or life-threatening interaction. Monitor closely. Use alternatives if available. Combination may increase risk of serotonin syndrome or neuroleptic malignant syndrome-like reactions. ECG monitoring is recommended, along with drugs that may prolong the QT interval.
Celexa (citalopram)
Serious - Use Alternative
citalopram and fluoxetine both increase serotonin levels. Possible serious or life-threatening interaction. Monitor closely. Use alternatives if available. Combination may increase risk of serotonin syndrome or neuroleptic malignant syndrome-like reactions. ECG monitoring is recommended, along with drugs that may prolong the QT interval.
Seroquel (quetiapine)
Significant - Monitor Closely
quetiapine, fluoxetine. Either increases toxicity of the other by QTc interval. Potential for interaction, monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.
The Prazosin is an alpha blocker and does not interact dangerously with the others. It is used to regulate blood pressure. It may however reduce clotting and platelet levels which is also a possible side effect of Celexa and Prozac. If you have any issues with platelets then that should be checked with a complete blood count (CBC).
Rule one, Talk to your Doctor before you change anything.