First step: breathe.
(That’s the first step for anything in life, really.)
It’s very common for women, especially heavyset women, to bleed periodically throughout pregnancy. Women store estrogen in their fat, and when there’s enough estrogen present for long enough, you have what’s called estrogen break through bleeding, and your body doesn’t much care if you’re pregnant or not. Fat women, having more fat, also have more estrogen stored and are thus more prone to bleeding between periods and while pregnant.
I bled every two weeks during pregnancy, and I was around 180 lbs when I got pregnant. The intermittent bleeding was darkish, brownish, and less than a normal period, but definitely more than what I would comfortably call spotting. Of course I worried every time, and every time it turned out to be nothing.
When I DID finally bleed for bad (so to speak), it was very different - bright red, (spoilered for the squeamish):lots of clots, and big chunks of firm tissue - some the size of my palm - that I could see little tubes in - those were blood vessels from the placenta. It was bright blood, it was copious, and it was just totally different. At that point I was at 23 weeks and 6 days, and they did a c-section to get her out before I lost her.
A very early miscarriage will expel what looks a bit like a grape - that’s the tiny embryotic sac, and a later one bigger chunks of placenta and fetal tissue, not just blood.
As **drachillix **says, there’s nothing that can be done for a very early miscarriage, other than to relax and lay down. Unfortunately, 25% or more of pregnancies do end in miscarriage, most even before the woman knows she’s pregnant.
As for the drinking: until you skip a period, or two weeks (on average) from conception, you pretty much have a get-out-of-jail free card, because the fertilized egg is still free-floating. It’s not hooked up to your system, getting things like food, oxygen, alcohol and drugs out of your system - it’s living off of stored energy in the original egg cell. So even heavy drinking or hard drug use before you miss a period is usually not anything to freak out about. There are rare exceptions - a medication used to treat male pattern baldness being one of them - but alcohol is usually okay. Do let your doctor know, of course, but chances are good that your drinking didn’t affect the fetus at all.