I have been having issues with diarrhea when eating things like dairy and all of that. I was wondering if I could be lactose intolerant?

That's typically how it's diagnosed. You can help to clinch the diagnosis by cutting out dairy for at least a week, and then eating some again. You need to find out if your symptoms really are related to lactose, or if you just had an intestinal virus that went away on it's own.
Note that many cheeses lose their lactose during the cheesemaking, so not all dairy has lactose. Google a list of what has, and how to read a typical label to figure it out on products you aren't sure about.
Lactose intolerance can run the gamut from very mild to very dramatic.

As joy mentioned, cut out dairy for awhile. You may want to go without for a couple of weeks or more just to be sure, as dairy can stay in your system for awhile. Years ago I was told by my doctor at the time that I had IBS. I just happened to mention it to a different doctor a number of years later and it was suggested to cut out dairy and caffeine for a month. Sure enough, it was like night and day. I can't tolerate either if I have too much... so I didn't have IBS after all.

You can try this: For 2 days, you can stop eating fruits and honey and beverages sweetened with HFCS or anything with added fructose or "polyols" like sorbitol and xylitol. This is to exclude fructose malabsorption as a possible causes of bowel problems. Then, one day when you have no bowel symptoms, you try to drink 2 glasses of milk (1/2 liter or 1 pint). If you have lactose intolerance, this will cause obvious abdominal bloating and probably loose stools. If no symptoms, you do not likely have lactose intolerance.