I think my fermentation has stopped early

[George7]

I'm currently doing a brown ale. The OG was 1.045 and the FG is supposed to be 1.010-1.012. It had a good thick layer of foam on top for the first few days (we started it last Tuesday), I'd say the ambient temperature probably ranges from 17-20C where it is, we've had warm weather recently, but it's not a room that's ever in direct sun, go doesn't get too hot. For the last couple of days, it has just had a thin layer of bubbles on top. The gravity is currently 1.025. I'm not sure if the layer of bubbles is just there anyway, or if it's a sign that there's still fermentation (albeit slow) going on. Does anyone with any more experience in the matter have any advice, or am I worrying about nothing?

EDIT: I don't have an airlock, but I have been sealing the lid, and as far as I can see, there's no pressure building up

 

[Glynn]

1. put an air lock on that thing, without one the pressure will find the path of least resistance. and possibly leave an opening for things to get in
2. let it go another week and then check it. what yeast did you use