When Loard Buddha saw his previous lives, He observed that what ever he practices in previous lives was affecting his mind in positive way (because of his Good karma’s).
How ever if one is practicing Bad Karma’s would result in your mind becomes dirty, which will take more time to become pure.
We are born with 3 things
Age (How long you are going to live.)
Jati (Born as Human or animal.)
Bhog (Results of Bad Karma done.)
For E.g. We often see some small children are interested in different activities, Which is a result of the impression of previous lives on their mind.
While you are in deep sleep, mind doesn't get energy from soul, which means you are not aware of sleep.
But as soon as mind gets the light of soul, it will start working and you will see dreams (you will still love your family in dreams, because Buddha said "You become, what you think").
So Yes, Love is real but you don't take it to next life the way you perceive it.
Yes attachment leads to Suffering.