You are not being silly at all! I am also usually a stomach sleeper. As a previous poster said, do it until it is uncomfortable. Believe me, you will know! I am 19 weeks and I sleep hugging a blanket. I kind of wrap one leg around it. You will have to try a few things and positions until you find one that works. It is much easier early on because I have heard that towards the end, just being able to get to sleep is a chore in itself. Also, the thing that everyone says about you shouldn't sleep on your back and only sleep on your left side is a good guideline, but you have to do what is comfortable. Don't stress out too much about sleeping in the "correct" position. When the baby gets bigger, it will even let you know if it is uncomfortable by moving around.
You've got a ways to go before this will be an issue for you (that is a good thing!!!!) I think I was about 16 or 17 weeks before I had a baby bulge & stomach sleeping was over. Your body will tell you when it's time...basically your body will just stop laying that way...you probaby won't even notice it happenning...you'll just realize one day that you haven't been sleeping on your stomach.
As for the side sleeping, I have a pillow I use to support my belly sometimes, but I didn't need that until the 3rd trimester (around Week 28) where the weight of the baby was finally heavy enough to start falling forward.
The use of pillows is to manage pain and aches from the weight of the baby, pressure on your pelvis, or just to get comfortable. Over the course of a few weeks, I graduated from 2 pillows to currently 6 pillows on my side of the bed (sometimes husband's pillows makes 8 if I'm napping during the day). I build various things to lay on depending on how I feel that day. I've had problems with my back since Week 19, so sleeping with pillows has become a way of life for me.
Don't get too worried over how you should or should not be sleeping this early on. At 5 weeks, the baby is about the size of a pinhead in there. You can do a Board search to learn about sleeping positions. We just had a couple threads on this just in the past couple weeks. Your body will tell you when things need to change.
On various baby websites and stores you can find special pillows that are used during pregnancy to help you sleep on your side. They are full body pillows and curve and wrap around you in just the right spots to support all the right areas. It goes from under your head to along your back so you can sleep on you side to in between your legs then to your tummy to support your belly. They are kind of expensive but they look great!
Those body pillows are great! I used them way before I was pregnant, and now that I am so far along, I fold it in half and use it to elevate my feet at night.
The only position I would say is rough after a while is sleeping on your back. I know I've had problems, because somewhere around the fourth month, the muscles in my hips started to loosen and get all weird, so if I was laying on my back for any amount of time it HURT to move, and you had to roll me off of the bed. It has something to do with your hips getting ready for labor. That isn't the medica reason for not sleeping on your back, but it was a good one for me
It's totally fine to sleep on your back. I'm 35 weeks (36 tomorrow!!!) and still sleeping on my back. I find it much more comfortable than any side position. If your doctor has a reason to tell you to stay on your sides (you get dizzy, the baby is stressed in some way, you're contracting early, etc) you should do what your doctor says; otherwise, back sleeping is totally fine.
My doctor says some women quit sleeping in their backs around week 28 or so because by then, the average weight of the baby, uterus fluid, etc. starts to gets to be too much weight on the spine for it to be comfortable...but then he says many women sleep on their backs up until the baby is born. He says to do what's most comfortable.
I am almost 21 weeks and i still sleep on either my stomach or back whichever way I can get comfortable, usually on my stomach with my leg in the angle like you said before. Baby seems to be doing just fine.