how do I find out if my random forresrt is overfitting?
The standard method to detect overfitting is to evaluate the model on both the training set and the test set. If the performance obtained on the training set is very high but much lower on the test set, then it's likely that the model is overfit.
Naturally this method works only with a proper test set: if there has been some data leakage from the test set to the training set, then the evaluation on the test is biased (the performance value is unreliable).