If you feel you have ruled out rational explanations for the phenomena that are taking place in your house, and they are still occurring on a more or less regular basis, document them. Keep a journal of the phenomena as they happen. For example:
A journal such as this could help with any formal investigation of the phenomena by experts.
If you hear unexplained noises, attempt to record them with a portable tape recorder. If there are physical phenomena of any kind, photograph or videotape them. Keep your journal, recording and camera equipment readily available so you can document the phenomena as it happens.
If, upon inspection, you discover an unwanted presence, try to educate yourself about the ghost, the house and various removal techniques, as much as possible. Since knowledge is power, using this knowledge can boost your confidence, lessen your fear, and provide you with the information you will need to restore your home back to the welcoming and safe environment you want it to be.
Contact your local priest. The priest will bless the house, hopefully at the least, making things better. If they don't, turn to the paranormal investigator, who will be able to remove the ghosts.
Who are the experts? There are hundreds of paranormal investigation organizations across the U.S. and Canada. You can find a state-by-state listing of many of them here. Make sure they are serious and have credentials before inviting them to your house.