So confused about the break up plz help?

Well we bn together for a lil over a yr and suppose to get married this month... Las week she broke up wit me saying she needed to exsperiance life a bit b4 settleing down.. We still txt everyday.. She took all her cloths when she left but left everything else.. She says she loves me but only sometimes she doesnt say it back.. Shes leaving for kansas tomorrow for 3 weeks and said shes stayin the night tonite b4 she leaves.. I do however know shes bn talkin to another guy and idk wat to think of it i know they spend time together cause he lives across the street where she is staying now.. i jus got mixed feeling and dont know wat to think... She said dont worry im stuck with her and it will b okay dont worry.. The other day i loaned her my jeep to use for the night.. Was that smart i always told her i would do everything i can to help her out... Plz help my confusion any need to worry???