Life has no objective meaning. Meaning is a social construct. As such, there's no concrete reason for which humans live. Everything you do will eventually evaporate, which means it doesn't really have any value in itself and thus you pursue these things for your happiness. Of course, if you care about others, then their happiness is also that of yours. However, emotions are evolutionary. They are not rational. Why should you prioritize your own emotions? Why care about them so much?

Thus, is there any scientific reason by which suicide isn't rational? A common misconception is that self-preservation constitutes the first measure of rationality, but aren't you starting with an unjustified premise? Why (rationally speaking) should you care about your well-being?