There are good, loving people who are also wondering and struggling and learning through this crazy life. They are doing all this thinking about themselves and their relationship with their God/Gods, just like you. Regardless of what anyone says, there are always going to be questions surrounding your religion or lack thereof.
I am not saying that you should question everything. If anything, I'm saying the opposite. Sometimes having faith is all you need and if that's you, please share that love with those around you. However, also remind them that it's okay if they are wondering about things you cannot answer.
Instead of making them feel like they can't have questions, remind them it's normal and that whatever God you preach loves them just the same. Not everyone has a testimonial that they can share, not everyone wakes up one day and does not need anymore answers. Sometimes, most times, people spend their whole lives wondering.
Feeling guilty can be a strong and powerful emotion, especially in combination with thoughts about religion. Feeling like you are not good enough or doing something wrong can cause dismay in your own thoughts that lead to days of stress. This stress is not worth dwelling over, you have one life to live and if you spend your days wondering and hating your thoughts, then you will never get the happiness you deserve.
You only have one life to live; be happy and stop overthinking things you will never get the answer to while here. Sometimes the answers are less about knowing and more about personal development and understanding that it's okay to just not know.
So, if you're laying in bed at night and you can't sleep because your head is full of questions, just remember that there are 7.5 billion people in the world, chances are they have wondered too.