From what I can tell as a non-medical professional, some of the most concerning warning signs are:
- Sudden weight loss (>10-15 pounds without a change in exercise or diet)
- Any kind of recurring pain, especially headaches
- Your poop is messed up
- Blood anywhere - coughing up blood, nosebleeds when you don't usually have them, blood in your poop or urine
- Mood or behavior changes (helpful if you have someone close to you who may notice this)
- Feeling fatigued even when well-rested
- Swelling or lumps anywhere
- Trouble sleeping
Which is a lot of stuff, but fortunately can be summed up as "If you feel consistently worse than you usually do, go see a doctor".
The key is to make your judgement of "I am indeed feeling consistently worse" within a couple of weeks, not a few months or even years while hoping it'll get better on its own. It's harder than it sounds - life is always busy and it's easy to tell yourself that your discomfort is mild and you can hold out a little longer. I waited too long to act on some bad heartburn and my few months of delay were rewarded with permanent damage to my lower esophagus...
when i was in my 20's a drank a lot of dr pepper. I switched to diet dr. pepper just by chance and it stuck as a habit. I lost so much weight so fast i went to the doctor fearing the worst. He did the math in front of me around how much less sugar i was consuming by that switch and it all added up. i was blown away.
- Sudden weight loss (>10-15 pounds without a change in exercise or diet)
- Any kind of recurring pain, especially headaches
- Your poop is messed up
- Blood anywhere - coughing up blood, nosebleeds when you don't usually have them, blood in your poop or urine
- Mood or behavior changes (helpful if you have someone close to you who may notice this)
- Feeling fatigued even when well-rested
- Swelling or lumps anywhere
- Trouble sleeping
Which is a lot of stuff, but fortunately can be summed up as "If you feel consistently worse than you usually do, go see a doctor".
The key is to make your judgement of "I am indeed feeling consistently worse" within a couple of weeks, not a few months or even years while hoping it'll get better on its own. It's harder than it sounds - life is always busy and it's easy to tell yourself that your discomfort is mild and you can hold out a little longer. I waited too long to act on some bad heartburn and my few months of delay were rewarded with permanent damage to my lower esophagus...