I feel horrible and hopeless after a workout??

I think I may be going through depression again, but Im not sure. I have extremely high anxiety, feel sad and gloomy. Have tight chest all the time, feel very down. After I workout (even crunches) I feel as if something is literally carrying me down and putting me down. The last time I jogged with full intensity for abut 5-10 minutes that I felt suicidal. Felt so horrible when I got off the tredmill that it felt as if I was burried in a hole. Is there a test I could take or anything to find out what Im going through? any ideas?