Wouldn't you say 我感觉很冷 or 我感觉很累, using 感觉 (gan3 jue2) instead of 觉得? 觉得 has a meaning of "think", whereas 感觉 has a meaning of "feel". 我觉得天气很冷 I believe would mean: "I think the weather is cold." Otherwise, in your other examples I would use 感觉 instead of 觉得。I am not a native speaker, so I am curious what they will say to this question!