Almost everyday my eyes get very itchy and teary seemingly out of the blue, why?

Suddenly my eyes, sometimes just one eye, get really itchy and start to tear up which is becoming a problem because I never know when it s coming and there s no way to stop it unless I try to rub my eyes which makes this "attack" go away faster. But when I m at school or out I often wear a bit of mascara so I can t rub my eyes and I just sit there awkwardly with my eyes closed shut waiting for it to go away... and it takes forever, plus I look like I was crying and people keep on asking me what s wrong lol. I tell people that I have an allergy because that s the most rational explanation but I don t actually know. I should probably go to a doctor but I don t have time so unless it s something very urgent I d rather just put up with it for a bit until I have some free time. Also, I ve had this sensation going on for maybe 6 months but recently it has been happening way more often, plus it s worse when I m outdoors. And I don t wear mascara all the time if that matters so I don t think it s related to that. But does anyone know how to deal with this?