I have a question. First let me explain my situation. I am unable to pay my full tithe (sometimes I can't pay any) due to bills and unexpected bills.
Have you considered the possibility that the reason you have so many unexpected bills is that you aren't tithing? I suggest you read the book of Haggai and see if there is anything in it that resembles your situation.
Jesus promised that if we put the kingdom of God first in everything we do, including our giving, he will supply all we need. There is an incident in the Old Testament that illustrates this.
So he arose and went to Zarephath. And when he came to the gate of the city, behold, a widow was there gathering sticks. And he called to her and said, Bring me a little water in a vessel, that I may drink.
And as she was going to bring it, he called to her and said, Bring me a morsel of bread in your hand.
And she said, As the LORD your God lives, I have nothing baked, only a handful of flour in a jar and a little oil in a jug. And now I am gathering a couple of sticks that I may go in and prepare it for myself and my son, that we may eat it and die.
And Elijah said to her, Do not fear; go and do as you have said. But first make me a little cake of it and bring it to me, and afterward make something for yourself and your son. For thus says the LORD, the God of Israel, The jar of flour shall not be spent, and the jug of oil shall not be empty, until the day that the LORD sends rain upon the earth.
And she went and did as Elijah said. And she and he and her household ate for many days. The jar of flour was not spent, neither did the jug of oil become empty, according to the word of the LORD that he spoke by Elijah.
(1 Kings 17:10-16 ESV)
In a sense the widow was in the same situation you are in; she simply couldn't afford to use any of her oil and flour to feed Elijah. She chose to do so anyway and God blessed her by supplying the food she needed to keep herself and her son alive for the duration of the drouth. Perhaps you should simply act in faith the way she did; the next time you receive a paycheck give the first tenth to God and then see if God enables you to pay all of your bills.
My present pastor has preached if you don't pay your full tithe you are sinning and damned to hell.
There is a mixture of truth and error in his preaching. If you don't give what God wants you to give you are sinning but if you have repented and put your faith in Christ
all of your sins, including your failure to give, have already been forgiven and you are in no danger of Hell. It sounds as if he doesn't have an accurate understanding of the gospel and I recommend that you start attending a different church.
While my parents and the pastor I grew up with says God understands my situation.
God understands your situation but do you? You are looking at your circumstances; you need to focus more on God and the help that is available from him.
Whenever a question like yours is asked on this forum it always leads to a discussion about whether Christians are required to tithe. Here is what the New Testament say:
Each one must give as he has decided in his heart, not reluctantly or under compulsion, for God loves a cheerful giver.
(2 Corinthians 9:7 ESV)
If you have decided in your heart that you should give a tithe then that is what you should give. The important point is that whatever you believe God wants you to give, you should give it first before spending money on yourself.