Nobody feels suicidal unless there is a wide range of reasons for that. Identify the source of the problem. But beyond that, here are some rough finger pointers.
1. Lose weight, get swole, be sporty and train primarily your strength muscles. Constitution muscles aren't enough, running or jogging as an exercise doesn't work. Use weights or go to a fitness center.
2. Self-improve career wise. If you already have a stable job work hard to make your employer as much money as possible and to dispell tensions in the work place and see if you can find a distance learning school to bring you to the next academic level in your area of expertise. Once you can rule out all ways in which problems with the job are coming from your end, see to doing something about it by either being transferred somewhere else within the broader structure, if necessary by bypassing your immediate employer and asking for help further up. If all of this does not apply, spread your wings and apply at other companies for a new job in the same field.
3. Get a gf. Completely override everything that 'academic' sources or social workers or humanitarian ad campaigns told you about women and read up on alternative sources. Women like to be sidekicks in a man's life, not the main character of their own. Project strength and confidence when engaging them and never underestimate the lows they can willingly stoop to. If you've been together for 3 years and you still aren't getting married and having a child on the way, ditch her and look to the next. And make it clear ahead of time that a relationship with you isn't just for the cummies. It's working towards getting married or fuck outta here.
4. Go to /pol/. No-one there forces you to believe everything you read without backchecking yourself, the only people who tell you to stay away from there are people who are afraid of you seeing what you might find there. There might be something deep inside you that you find hard to describe, that over the years gets more and more torn, more and more tense, and fills you with an uncontrollable rage that you can neither guide anywhere coherent nor explain. If it is that, it can give you nervous breakdowns. Go to /pol/, and it will eventually relax completely. At least on that deep, hard to describe level you will be relaxed like you haven't been in a long, long, long time. This feeling that was tearing at you, is your cognitive dissonance. You are being fed and are attempting to believe information that is mutually contradictory and at the same time, the information you attempt to believe doesn't match any life experience you gather and this rage is your brain trying to process and make it match and gradually failing over the years, because - as mentioned before - it is mutually contradictory. It cannot match.
5. Arm yourself. Whether it is by completely regular means in a country where the government hasn't successfully disarmed the population, or through an excuse like regularly participating in a shooting club, just make sure you have at least a firearm, preferably with some ammunition stored somewhere safe in case something à la SHTF happens.