First Time Fermenation - Did I screw it up?

First time brewer here and I'm not sure if what I'm experiencing is normal or if I've done something wrong...I'm making an american amber ale from extract (6lb LME and 1 lb DME). My OG was lower than expected (1.041 instead of 1.056) which I cannot explain really...My main problem is that I used one rehydrated packet of dry Danstar Windsor yeast and saw very vigorous fermentation within 24hrs (which actually caused foam to bubble through the airlock -- is that really bad? --) but after a day or so the bubbling almost stopped completely through out the next two weeks. At this point the gravity was only around 1.025, should i have just let the fermentation continue? Should i have pitched more yeast after the spill off? Thanks to anyone who can help...

I highly doubt your OG was 1.041. Chances are, you had a bad reading. It's nearly impossible to be off with extract.

As for your FG, it's fine. Extract beers will usually finish out a little higher than normal. Next time you get krausen in your airlock, just clean it, sanitize, and replace. No biggy.

Yeah, unless you REALLY screwed up your dilution and have no way of accurately measuring the volume in your fermenter, then I'm pretty sure your OG was higher than you measured... you gotta stir that sucker up real good before measuring!

Don't worry about the airlock mess - not a big deal... I'm sure the other 99.99999999% of the yeast that remained in the beer were able to finish the job.

It's ready for bottling when it's clear... if you can't see it because you're using a bucket, don't be opening it every day. Just wait another week.

I don't know what you use in your airlock, but I use cheap hard liquor like vodka. At 40% ABV, it keeps that area nice and sanitary and if some of it happens to fall in your beer due to temperature suckback or due to krausen clogging it, it won't harm your beer at all. Otherwise, clogged airlocks aren't usually an issue unless it cloggs completely and then gets blown off like a rocket from pressure buildup. If you store your beer out of sight during fermentation, your beer could be exposed to ambient air and could get infected. As said earlier, just quickly cleaning the airlock and replacing it is just fine. It's always good practice to keep an eye on your beer the first 2-3 days to catch that kind of thing before it becomes a bigger problem.