Welcome to the forum yolandi.
Going to the doctor is the best and safest way to find out if you have allergies. Do you have insurance? If not, just call and explain that you want to get allergy testing but you have no insurance. Ask what it would cost!
I am totally leery of quacko home tests. They're not tested and proven like the tests real MDs can give you. You should start with skin testing. That'll show any regular allergies. Even the blood tests a doctor can give you aren't very accurate.
Now intolerances are a different story, but there's no test you can send out for. You have to do "challenge testing" (see search box at the top of the page) yourself. BUT DON'T DO IT UNTIL YOU SEE THE DOCTOR! If you have bad reactions it can be life threatening. Intolerances cause reactions other than hives and throat closing. I get gastric reflux and rapid heart beating, sometimes for many hours.
Keeping a daily journal of foods you eat, medicines, whatever is happening that you think may cause your allergy reactions (spring trees blooming, grass pollen high in your area) may help you figure out your triggers by yourself. Write down the time, what you eat, plants blooming or whatever, and your reactions. This takes 3 months or more to start to get a handle on your symptoms.