Why have you been given this medication? Has the doctor explained this to you?
Yes this medication can cause at least some of what you describe. Usually only short term, 2 weeks or so though.
Venlafaxine is an anti-depressant, and can be causing your symptoms, sounds like it's a bit too much for you, along with you having some of the side effects of the medication. Regardless, you need to speak with your cardiologist about this and the impact it may be having on you. Take care...