Clearly that is something that you don't understand. You must expand your understanding by pushing doubt out of the way and trying to learn the answers to your question.
John 14:18-21 [with my emphasis], "I will not abandon you as orphans, I will come to you.
In a little while the world will not see me any longer, but you will see me; because I live, you will live too. You will know at that time that
I am in my Father and you are in me and I am in you. The person who has my commandments and obeys them is the one who loves me. The one[
av] who loves me will be loved by my Father, and I will love him and will reveal myself to him.”
Not only can a completely human person be in the Father, but s/he can also be in Christ (who is also God). If you try to understand this by normal logic, it won't work. You must
expand your thinking and try to conceive how this is possible. Pray and ask God to show you how this is possible. (You will have to open your mind beyond normal thought.)