Thankfulness

Apparently God is trying to teach me a lesson on being thankful this week because that seems to be where all my thoughts are this week. Last night I was laying in bed thinking about how uncomfortable I was because William was in playing in my ribs, I was having bad reflux, I had already gotten up three times to go to the bathroom since I went to bed, I was hot, so on and so on. I suddenly realized I hadn't thanked God for the miracle growing in my belly. After that I got to thinking, are we supposed to be thankful for everything we experience even the bad? Is a cancer patient supposed to thank God for the cancer that could take their life? I did a study this morning and I'm still a little fuzzy on what God wants from us when it comes to being thankful. Obviously we are to thank him for everything in our life, but what about the bad stuff or the uncomfortable stuff? I do remember hearing that we should thank God for whatever test and trial we are going through because we are still blessed and God has a plan for our lives and the test or trial we are going through is part of that plan and even though we don't know what the experience will teach us, we should thank God for that lesson. In 1 Thessalonians 5:18 it says, "Give thanks in all circumstances, for this is God's will for you in Christ Jesus."
So, my what I learned is I'm still confused. I'm still going to have to do some research but this may be one of those things that God is going to have to show me himself. If I am to read into the Thessalonians verse, I would say that we are to thank God for EVERYTHING in my life no matter how difficult the experience is. This is definitely something I'm going to have to work on. Please feel free to add your two cents in on this subject because I am totally unsure and a little lost.