Hi. Relationship breakups are quite stressful & lead to lots of automatic negative thoughts, hopelessness, frustrations & painful ruminations. You need to get present to these feelings in the context of breakup. Then it is likely to make sense, although are uncomfortable. Noticing them objectively & not subjectivity, will help you to come to terms gradually. Focus on keeping yourself occupied & doing things which you used to enjoy while you practice above would help. If things are worsening or there is no improvement, please consult a Psychiatrist at the earliest. Hope this helps. Best wishes.
Try do divert yourself
Do some exercise and relaxation
Even if thoughts are coming up in your mind dont give much attention
It will take time
Accept these issues you will overcome it soon