One thing that could help with anxiety is starting with very low doses. It's possible to take so little that there are no obvious effects. This is called a "sub-threshold" dose, and is also known as a "microdose".
It's still possible for the substance to have some subtle, interesting effects at these doses. Things such as an increased creative ability, enhanced energy, and insight. Some people take microdoses of psychedelics to improve their problem-solving abilities. At these doses, your anxiety should be much lower than if you took a regular (nevermind a mindblowing) dose outright.
After a number of such microdose trips, it's possible to slowly increase the dosage. Hopefully, as you do this, you'll become more familiar with the territory and know what to expect, and there will be less fear of the unknown and of the novel effects you will likely experience.
That said, there can be some negative effects -- particularly nausea. Also, it's dangerous to pick wild mushrooms, which can be poisonous if a mistake in identification is made. There's a saying in the mycology community: There are old mushroom hunters, and there are bold mushroom hunters. But there are no old, bold mushroom hunters.
Ideally, you'd only partake of mushrooms under the guidance of an experienced mycologist (and after having done a lot of research yourself about proper mushroom identification).
Unfortunately, an experienced mycologist is not always available, and the mushrooms available on the black market are often dried, crumbled, and in a state that's virtually impossible to identify anyway. The potency and even the active ingredient in such samples is very questionable. They could easily be laced with LSD or some other drug and you may be none the wiser.
Some people advocate only ever taking synthetic compounds like LSD, which are at least less likely to be counterfeit when taken as blotter or microdots (because they are so small that no other drug would be potent enough to do anything at that dosage). However, some newer designer drugs are almost as potent as LSD, and are potentially more toxic. So it's not clear what should be recommended, if one is concerned about side-effects, identity of the compound, or toxicity. Perhaps growing or synthesizing one's own would then be the safest route. But, of course, depending on the laws in your jurisdiction and depending on your skills, these options may come with their own risks.