Is there any way to calculate the true,false positives and negatives for a regression problem
I believe that there's no actual function in sklearn library that does that. However, that concept is relatively easy to implement: you can loop and compare each y_prediction with the respective y_true_value and increment TN, TP, FN, and FP accordingly to a certain threshold. For example:

if abs(y_pred[i] - y_true[i]) &lt;= threshold: 
     TP += 1
 elif abs(y_pred[i] - y_true[i]) &gt; threshold:
     TN += 1
 ...

Don't forget to reverse transform the scaling on y_true and y_pred values first.