My gums are very sensitive lately. They are a little swollen in the front. I didn't brush or floss that often and I smoke. Maybe gum disaese?

Gingivitis. Start with better oral hygiene, or say hi the prmature tooth loss. Also say hi to your dentist.
Periodontal disease. It sounds like that you have periodontal disease. It could be plain gingivitis (early stage) or periodontitis (advanced stage). I suggest you see your dentist to decide if you need deep cleaning (scaling or root planing.
Absolutely. Seems like you have correctly self diagnosed. Stop smoking, floss, antibacterial mouthwash like listerine and start seeing your dentist. Dont forget, smoking is a risk factor for oral cancers, a terrible disease.