Let's come back to your OP.  When you have closed the trade, was that according your original plan for that trade?  If so: pat yourself on the back instead of thinking about how much you would have made if not following your plan.  Executing and managing a trade according to the plan is the most important exercise a trade can do.  If you have followed your plan, you did a good job no matter what happened afterwards.

If you did not follow the plan: ask yourself why.  What was it? Fear the trade could turn against you?  Fear you could lose the already gained profit?  Also ask yourself, how can you avoid this in future?  Probably trading smaller could help.  Add your thoughts and action plan to your trade journal.

All traders have closed trades before they have originally planned to do.  That's part of the evolvement in becoming a better trader.

So either way: the question is, can you accept the market is rallying further even though you have closed the trade according your plan or can you work on yourself to have the discipline to follow your plan?  And: don't look back, the next trade where you can do better is right around the corner.