Gas and Oil Home Heating Furnaces - Utica furnace - no heat

I'm a new homeowner and know almost nothing about furnaces. My furnace was working up until last night and now it turns on and is using gas, but no heat is coming up the baseboards. The furnace has a self ignitor pilot and isn't terribly old (maybe 5 years). My gas fireplaces works - so I don't think it's a problem with the line.

Does anyone have any suggestions as to where I should look for a problem? I wish the owner's manual had a trouble shooting guide...

What do you mean by using gas? You have pilot and main burner running?

Baseboard as in hot water heat?

If hot water heat, maybe the pump has gone out.

If forced air, the blower may have gone out. Check the blower by switching the t-stat fan switch to "ON", and see if the blower runs. You may leave it there if you need to heat the home up.

Thank you for your post. Turns out that the sensing port on the blower was plugged up. I had some one come fix it for me b/c I had no idea how to get it off + clean it. Not nearly as costly as I feared and it works great now.