Overthinking is from the devil itself.Don't sit there and think what if or why.Don't drown in your own misery.Everything happens for a reason.It is the Qadr of Allah.Remember Allah can see everything.He sees conversations you don't see.Allah sees situations you don't see.Allah does not take anything from someone without a reason,its for a good reason.Sometimes it's best that your heart gets broken so that your soul is saved.Even if you cannot handle it ,remember Allah always gives his hardest battles to his strongest soldiers.Learn to accept things as they are.Ask the Almighty to constantly guide you.What you can't control,let Him take over.Stop feeding your mind negative thought s and self doubt.Love yourself and
remember,the Almighty only wants the best for you.
And let me impress upon you the importance of Tahajjud (if you're not familiar,look it up - its worth knowing).'And from (part of) the might,pray with it as additional (worship) for you;it is expected that your Lord will resurrect you to your praised station'(Quran 17:79).Trust me,you'll feel the difference.
