Constant feeling of wanting to vomit

Hi,

For the past few weeks I've had a feeling like I want to vomit. I get the usual ticklish feeling you get at the bottom of your throat just before you vomit but nothing ever happens.

Initially it was pretty mild but in the past couple of days it's got progressively worse to the point that I needed to take the day off work today and I'm constantly gagging, because of this I am now having trouble eating,

Now that it's gotten worse I am having trouble sleeping even though I am extremely tired. I've also had headaches but that's not unusual (I've always had headaches) and with the lack of sleep seems like a side effect rather than directly related.

I've tried googling and searching but as the symptoms are so generic there is nothing that pops out as an obvious cause and I was hoping with all the information someone who had more experience might be able to narrow it down.

I'm a guy, 22. I've tried all the usual stuff like drinking a lot of water, eating more healthily, trying to get a balance of vitamins etc since I first started feeling ill a few weeks ago.

Is this likely something that will just pass with some rest, or do I need to see a doctor. What are the likely causes?

Any advice would be appreciated.

Thanks,

Joe