Estar inquieto/a por – to be anxious or worried about
Estar preocupado/a por – to be worried about
Inquietante or preocupante (adj) – worrying or disturbing
No lamentes lo irremediable – don’t worry about something that has no solution
No llores sobre la leche derramada – Don’t cry over spilt milk
No te ahogues en un vaso de agua – Don’t drown in a glass of water or make mountain out of a molehill. “De un granito de arena no hagas una montaña” is the literal translation of the latter. In Spanish you can also say “No hagas una tormenta en un vaso de agua” or simply “No exageres”.
No te aflijas or no te alteres – Don’t get upset
No me desvela – I won’t lose any sleep over it. Desvelar means to stay awake. El café me desvela means that the coffee keeps me awake. The noun desvelo can mean anxiety or worries
Ofenderse – to get upset or offended
Preocupón – a person who worries a lot
¡Tranquilo/a! – take it easy!

Tiquismos

¡Al chile! – Are you kidding me? No shit? Really? Cuando María le dijo a Carmen que iba a visitar Italia la próxima semana, Carmen dijo “¿Al chile?”. When María told Carmen that she was going to Italy next week, Carmen said, “Are you kidding me?”
¡No te agüeves, mae! – Don’t get upset, man!
Parársele la peluca – Figuratively it means to get upset. Literally to have your wig (hair) stand on end. A José se le paró la peluca. Joe got upset.
Tranquilo como Camilo or Calmado como el pescado – Take it easy.