How much vitamin d recommended and which one should i take if i've been consistently low in the past? i was a 7. don't get enough sun bones feel weak.

There is no way: you can tell if your bones are "weak" by how they feel. If you level is really 7, you need several months of approx 50,000 u of D3/week. Once your levels are normalized, a lower dose of approx 2000 u of d3/day should keep it stable.

50,000 IU/week &: wait ~3 months to recheck. Remember that it is D3 that counts, Not D or D2. BioTech Pharmacal D3-50 50,000 IU http://goo.gl/pS8C2i (from sheep lanolin, sheep raised for their wool) is one of the few supplements, either Rx or OTC, which I have found to essentially always work & take myself along with wife. The dose which works long term is quite sensitive, aim for ~70-80 ng/ml & small adjustments.