1/ you should not have broke up with her if you were unsure.
2/. You should not have slept with her after the break up.
3/. There should have been no contact. Between you.
4/. You only want her now coz someone else has her
5/. Stop being selfish and leave her alone!
You have been very unfair to her. You broke her heart, continued to sleep with her knowing she was upset and vulnerable, gave her false hope for 5months, and when she has finally accepted its over- you try to get her back.
You have really messed up here, she wont forgive you and you need to stay away from her so she can deal with the loss and move on with her life.
You may regret all this now but its too late!