i cant lose weight! advice?

ok so semi long story i suppose; all my life i had been extremely thin(5'8 and 115) until college i started slowly gaining, which was ok because i was only at an average weight instead of overweight. fast forward a few years to 2014, i was diagnosed with lupus and gained a few more pounds over the next year when i moved out of state with a boyfriend. after moving back home i got on the scale for the first time and was 259😳. i did lose 20lbs after moving back without working at it(i finally was out of a very stressful situation) last october i joined a gym and began working out and watching what i ate(low carb, no sweets or cokes, only waterand lots of veggies and chicken or fish), and i was going to the gym at least once a day. ive always started on the eliptical or bike and usually do at least 35-40 mins on those before i start on weights, which i usually do for about an hour/hour and a half(rotating days and what i work out). the problem is, ive only lost about 10lbs in the last year(and i havent lost a large amount of fat either). ive been to numerous drs and had all kind of tests done to try and figure out the reason but no one seems to find anything out of the norm. any

suggestions?