This is something I am studying a lot right now, but I haven’t wrapped my head around it all yet to really serve you. Here are some thoughts though. Sometimes we “fall in love” with God and sometimes we “fall out of love” with God. It’s the same with human relationships. When we are “in love” we desire to love God. This desire manifests itself in wanting to worship and serve God as well as follow all his commandments. Doing good is easy in these moments. When we are “out of love”, it’s just the opposite. We have no interest in God. We just want to be selfish and do what we want to do.
This can change at anytime. We might be in love with God one day, but out of love the next day. It might be longer, maybe 3 months being in love and 3 months out of love, or any combination. You see love is both a feeling and a choice. When you have the feeling, love will be easy. When you don’t, it will be difficult. You just have to keep doing the right thing even when you don’t like it. Eventually, the feeling will be back. You are in love with God again. To get through these periods, we need persistence, perseverance, or patience whatever you want to call it.
Of course, it would be much better if you never “fell out of love” with God. There are certain things you can do to foster this. I don’t have any books to recommend, but there are some good articles online if you search for “catholic how to love God”. Just off the top of my head, one way to foster the feeling of love (or desire to love God) is counting your blessings and thanking God for them.
I’m sure you have had times when someone did something for you and it really touched your heart. Maybe you were in real trouble and they got you out of it. It could be even simpler like a friend giving you the perfect gift for your birthday. By seeing God’s blessings for you in your life, it may touch your heart and bring you close to God again. There’s more than this, but I can’t remember. Do some searching. I’m sure you will find some good resources.
Still, there will always be some of this back and forth in your relationship with God as long as you live on earth. It’s only in heaven that we will always love God. In that sense this is somewhat normal. For the spiritual side of things, it can be really good to talk to your priest. You can do this in the Sacrament of Confession. You won’t have a lot of time, but your confessor’s advice might really help.
However, there is a possibility that you are going through depression. I have had depression before and it makes you unhappy or disappointed about everything. Nothing, not even your most favorite things, makes you happy. If this is the case you should see a mental health professional. If you are under 18, you should talk to your parents about this. If you are over 18, call around until you find one that sounds like a good fit. There are tons of resources about this online as well. Just search for “help with depression”.