Exercise works for some people (did for me) as it releases endorphins - this can include speed walking with a pushchair or baby in a sling if getting out on your own is hard work. Gettting your heart rate up and breaking a sweat for at least 20 mins. And doing things that make you feel good e.g. being outdoors, among trees, swiming, whatever...
But agree, if feeling suicidal, best to get some help. You don;t necessarily need to get medication or counselling, but they do help. You need to work out what will work for you though, and don't rule anything out until you have given it a good try (at least a month I would think)
Good luck. Hope you feel better soon