The first time I took mushrooms they were fresh (A-dam) and that was just perfect. No nausea or anxiety.
However, the first few times I took dried mushrooms I had problems like you describe. Shrooms are really emotional, and feeling sick while on them can easily send you on a downward spiral. To be honest, I think most of the time shrooms have a bit of darkness to them. You gotta be able to face that shit once and a while. It is hard, but well worth it in the end.
Anyway, like I say, feeling sick doesn't help any, so here is a recipe that should help keep'em down.
Get some tea. Any tea that comes in a bag will work, so choose something you like.
Take your tea bag and carefully remove the staple at the top to open it. Set the string with the little square piece aside for later.
Place your mushrooms in the tea bag.
Tie off the top of the tea bag with the string.
Heat water to boiling, then let it sit for a minute or two to cool off a bit (if it is too hot you risk destroying the psilocybin).
Add tea bag and warm water to a mug.
Add lots of lemon juice (more than you would normally like). An acidic solution aids in the extraction (you can actually do extractions with just citrus juice as well)
Add honey to taste. If you added enough lemon juice it will probably be quite a bit.
Steep at least 15 minutes and enjoy.
If I didn't have the opportunity to make tea I always just ate caps. I understand that they are really no different from the stems, but something about eating caps was easier to stomach for me, and led to less anxiety and uncomfortable-ness. It is worth a try, if nothing else works for you. Hooray placebo!
Also, chocolates are good. Just powder the mushies in a coffee grinder and mix with melted chocolate (hooray microwave!) and poor into mini-muffin tins (make sure to use wrappers/pam spray).
And Lemon Tek: Mix that shit with lemon juice, let it sit for a few hours/over-night and filter through a bit of cloth.
Good luck, hope this is helpful. Remember to be safe!