Hi Yuppers!
You said :
"In church yesterday the pastor was talking about finding our ultimate joy in Jesus. I don't know how to do that by myself."
You also asked how to find inner peace.
The Bible says that Jesus said :
"Peace I leave with you; my peace I give you. I do not give to you as the world gives. Do not let your hearts be troubled and do not be afraid." John 14:27
Jesus said also:
"And I will ask the Father , and he will give you another advocate to help you and be with you forever- the Spirit of truth. The world cannot accept him, because it neither sees him or knows him. But you know him, for he lives with you and will be in you. I will not leave you as orphans; I will come to you. " John 14:16,17
As I was reading that chapter for this reply I was thinking that that whole chapter might help you (John 14) also with the other things you mentioned. Take note too that in the NIV the chapter is called "Jesus Comforts His Disciples."
Your issue here too , Yuppers, is that you can't generate Jesus's joy nor can you give yourself His peace. HE has to GIVE those things to you. So ask Him for both things and then wait on Him to do so. The world says that you have to DO things, or GO places or talk to people, read books etc. to get peace or joy. But GOD and JESUS says that they will GIVE TO YOU those things. So you can operate on your own fallen efforts to get something that only God and Jesus can give you. Think of it like this, you buying your own Christmas gifts , which will not be perfect as God's ways and things are, or asking God to give you His Christmas gifts , what He said that HE WOULD GIVE YOU, which will then be perfect.
Pay attention to when you are trying to do the Christian walk on your own efforts. Yes, there are some things that you do on your own like read the Bible, etc. but there are things that are spiritual that God has to give you and do for you. Like giving you HIS peace and HIS joy. Those are HIS things to give. So ask Him and then wait on Him. He loves you.
AND I will say, from experience, when God gives you His peace and fills you with His Holy Sprit you won't feel alone and your house won't feel empty. You and your home will be filled with His Holy Spirit and you plus Him does not equal being alone. You might have times of feeling lonely but you will not be alone. : )