a mindful meditation requires focus.
instead of thinking about all the problems you have, focus on relaxing those few minutes and to get some peace of mind.
overthinking will only add more stress and anxiety which is bad for your mental health.
first you need to sit or lay down in your bed
take at least 5 deep breaths and relax, forget the world, worry, and all the stress you've been through, lose yourself in another world of relaxation.
personally i think the best time to meditate at night, to sleep with positive vibes and wake up all clean and ready to fight the world in the morning.
to conclude i would say that mental health is as important as physical health, don't let negative thoughts drain you and eat up your energy, don't just feed your body healthy food to stay in shape, feed your brain too some positive thoughts and useful information that may help your future self. if your body is a temple you'll live in so is your brain. change your mindset, change your life cause you'll never have a good life with a negative mindset.