How do we move forward when we are going through the struggles and holding onto regret?

Lay it down at the foot of the cross.

“for it is God who works in you to will and to act in order to fulfill his good purpose,” Phillippians 2:13

Hold onto God with all your heart, with all your soul, and with all your mind. Lean on Him and know that He will hold your hand through the storm. Make no room for regret. Instead, trust. And finally, know that our purpose is to know our Lord Jesus and make Him known. Let His will be done and trust in the Lord.