Power lifting/other forms of exercise

So I'm a tiny thing. 5 foot, 95 lbs sopping wet. I Have an 8 month old and I work nights. So it's a bit harder to get out and exercise. Especially with it being so rainy or cold right now (I could exercise while pregnant due to restrictions and couldn't begin again really until 6 months pp.) Before I got pregnant I was training with Marines because I was enlisting, but I can't now unless I want to sign over rights to my daughter. So I'm enlisting in the National Guard and I should be swearin in in late January. But I need to gain muscle weight. I lost like all mine I gained from training with the Marines when I got pregnant. ): so what are some Good exercise routines I can do? I want to power lift, I just don't know a good... Routine or whatever and whatnot. Anything will be helpful honestly! Thanks! (: