Innovative exercise?

Hello. I am very much untaught as far as fitness is concerned. I've recently taken to monitoring my caloric intake and striving to make healthy decisions nutritionally, but it seems that it's only a certain element of the formula. I am nearly entirely sedentary. I'm home schooled and have rather encumbering social anxiety, so very seldom emerge from my room. I stay in bed. Of course, I am mobilized by bathroom needs, cooking, and traversing the house for items I may need during the day. I venture outside perhaps once or twice a week to aid in shopping or visit my boyfriend and family members.

I'm not content with appearing small, but feeling weak. I want to be stronger. I have been reading a plethora of success stories from people who have underwent positive transformations by lifting, strength training and becoming more fit. Now, I have no money for a gym membership, am fearful of the outdoors, and am not educated in this subject. Can anyone suggest exercises I can perform that would strengthen my effete self? I want to be physically capable, have definition, and feel better.

If it's pertinent, I am 5' 5" and 100-108 pounds. I apologize for the lack of precision, but I haven't had access to a scale in about a month. Definitely have not gained, though.

Thank you!